Risk-Adjustment Models
Select a Model Type: Post-Transplant Survival OPO Donor Conversion Rates Select an organ: Kidney (Deceased Donor) Kidney (Living Donor) Liver (Deceased Donor) Liver (Living Donor) Lung Heart Kidney-Pancreas Select survival type: Graft Patient Select transplant follow-up term:   1 Year 3 Year Select a Format: HTMLPDF (Contain All Organs)

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Table of Contents

Introduction

Center Summary

Table 1. Waitlist Activity

On Waitlist at Start
Additions
Removals
On Waitlist at End of Period
Additional Observations and Caveats

Table 2. Characteristics of Waitlist Patients

Race
Ethnicity
Age
Gender
Blood Type
Previous Transplants
Peak Panel Reactive Antibody (Kidney, Pancreas, and Kidney/Pancreas Programs Only)
Primary Diagnosis Group (Not Shown for Pancreas and Kidney/Pancreas Programs)
Years Since Diabetes Onset (Pancreas Programs Only)
Recipient Medical Urgency Status at Waitlist (Liver and Heart Programs Only)

Table 3. Transplant and Mortality Rates among Waitlist Patients

Count on Waitlist at Start
Person Years for Transplant Rate
Removals for Transplant
Transplant Rate (per year on waitlist)
Expected Transplant Rate
Ratio of Observed to Expected Transplants
95% Confidence Interval
Comparison of Rates
Person Years for Mortality Rate after Being Placed on the Waitlist
Number of deaths
Death Rate (per year on waitlist)
Expected Death Rate

Table 4. Waitlist Activity and Patient Vital Status at 6, 12, and 18 Months Since Waitlisting

Table 5. Percent Transplanted (Excludes Living Donor Recipients) for Waitlist Patients at This Center

Table 6. Time to Transplant for Waitlist Candidates

Table 7. Transplant Recipient Characteristics

Patient Count
Race
Ethnicity
Age
Gender
Blood Type
Previous Transplants
Peak Panel Reactive Antibody (Kidney, Pancreas and Kidney/Pancreas Programs Only)
Body Mass Index
Primary Diagnosis Group (Not Shown for Pancreas and Kidney/Pancreas Programs)
Recipient Medical Urgency Status at Waitlist (Liver and Heart Programs for Patients with Deceased Donors Only)
Recipient Medical Urgency Status at Transplant (Liver and Heart Programs for Patients with Deceased Donors Only)
Recipient Medical Condition at Transplant
Recipient Life Support Status at Transplant

Table 8. Summary for Characteristics of Transplant Donors

Patient Count
Cause of Death
Age
Race
Ethnicity
Gender
Blood Type
Expanded Criteria Donors

Table 9. Summary for Characteristics of Transplant Operations

Patient Count
Cold Ischemic Time (Deceased Donor Transplants Only)
Relation With Donor (Living Donor Transplants Only)
Level of Mismatch
Procedure Type
Dialysis in First Week After Transplant
Sharing (Deceased Donor Transplants Only)
Median Length of Stay

Table 10. Graft Survival Rates

Number of Transplants
Graft Survival
Expected Graft Survival
Ratio of Observed to Expected Graft Failures
95% Confidence Interval
P-value
Comparison of Rates
Follow-Up Days Reported
Maximum Days of Follow-Up
Review Criteria (preview site only)

Table 11. Patient Survival Rates

Number of Patients
Patient Survival
Expected Patient Survival
Ratio of Observed to Expected Deaths
Random Variation
95% Confidence Interval
P-Value
How do the rates at this center compare to those in the nation?
Percent Retransplanted
Follow-Up Days Reported
Maximum Days of Follow-Up
Review Criteria (preview site only)

Technical Notes on Computing Expected Patient or Graft Survival

Model Fitting Methods
Missing Data
Notes on Diagnosis, Ischemia Time, and Other Continuous Variables
Calculation of Individual Expected Survival

References

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Introduction

There are 12 tables and a summary table that report statistics for individual transplant center programs. When the description below refers to the statistics for a "center", it actually indicates the statistics for a particular transplant program (specific organ) at that center. The statistics in these tables are based on data available from the Organ Procurement and Transplant Network (OPTN) as of April 30, 2010. These tables report organ procurement and transplantation activities. Generally, the same conventions that have been used previously by the OPTN to tabulate donors, organs, transplants, and transplant operations were used here. These tables are described individually below. A table is suppressed if there are no patients for that specific table for your center.

Center Summary

The center summary table presents selected statistics for your center that can be found in greater detail in Tables 1-11. These statistics provide summary data as a reference for frequently asked questions.

Table 1. Waitlist Activity

Table 1 presents the movement of candidates on and off the waitlist between January 1, 2008 and December 31, 2009. Candidates are placed according to the center at which they were waitlisted. This information is given for the center and, for purposes of comparison, for the U.S. as a whole. The data are presented as counts of candidates for a given center (the leftmost pair of columns for the two time periods reported) and as percentages of the candidates on the waitlist at the start of the period (the last three columns give statistics for the center, the OPTN Region, and the U.S.). The three columns on the right of the table report values as percentages to allow comparison of patient counts at the center, OPTN region, and national levels of aggregation.

The data exclude candidates who received a living-donor transplant without ever having been waitlisted and candidates waitlisted for pancreatic islets.

On Waitlist at Start
The number of patients at the center at the start of a period is defined as the number of patients who were placed on the waitlist before midnight, of the previous day and who had not been removed as of that time.

Additions
The number of additions to the waitlist for transplantation at the center for a given period is the number of candidates whose listing date was during that period.

Removals
The removals of candidates from the waitlist are reported according to the reason for removal (e.g. "Deteriorated", meaning the condition of the patient had deteriorated to the point that they had been removed from the waitlist). The available removal codes are: transferred to another center, received living transplant, received deceased donor transplant, died, medically unsuitable, deteriorated, recovered, and other reasons. The removals are counted only if they occur during the period.

Percentages are relative to the waitlist at the start of the period, dividing the number of candidates added/removed/still on the waitlist during the period specified by the number of candidates on the waitlist at the beginning of the period. The result is multiplied by 100 to produce the percentage.

On Waitlist at End of Period
The number of candidates on the waitlist at the end of a period is the number of patients on the waitlist at the end of the prior period, plus the additions during the period, minus the removals during the period. The number of candidates in a program at the end of the first period is the same as the number of candidates at the beginning of the second period.

The percentage of additions and removals are added to and subtracted from, respectively, the 100% on the waitlist at the start of the period to yield the percentage on the waitlist at the end of the period. Note that if more candidates join the waitlist than are removed during a period, the "percentage" of patients on the waitlist at the end of the period will be greater than 100%. For example, if the U.S. percentage for kidney candidates on the waitlist at the end of the period were 108.8%. The additional 8.8% would represent the growth of the kidney waitlist during the period. Note that it is possible for the number of additions and removals during a period to exceed the number on the waitlist at the start of the period, so that the percent of additions and removals can be greater than 100%.

Additional Observations and Caveats
The number of candidates removed from the waitlist for various reasons at a given program is dependent upon data submitted to the OPTN and provided to the SRTR. For example, it is possible that a candidate is reported as removed from the pancreas waitlist for a living donor transplant, even though no such transplants were performed at that center, according to information contained in the OPTN database. We have observed only a small number of such data anomalies, which are likely due to discrepancies in the data reported by programs on different data collection forms. Data used for transplant tables later in the report are derived from different elements in the database and, therefore, counts of waitlist removals for transplant and counts of reported transplants may not always correspond.

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Table 2. Characteristics of Waitlist Patients

Table 2 shows the distribution of various characteristics among waitlisted candidates for each organ in a particular center, in each OPTN region, and nationwide. Candidates are placed according to the center at which they were waitlisted. These data are presented both for new candidates whose listing date was between January 1, 2009 and December 31, 2009 inclusive and for all candidates who were on the waitlist on December 31, 2009. All data are obtained from files of current waitlistings or previous waitlist removals.

At the top of each column, the "(N = )" shows the number of candidates whose data were used to calculate the percentages in that column. The percentages are reported for each of the characteristics described below. The percentages within each characteristic add to 100%, except for rounding anomalies. Candidates with missing information are in the "Unknown" or "Other" categories.

Race
The percentage of waiting list candidates in each of five race categories is reported. Race and enthnicity are reported together as a single data element, reflecting their data collection (either race or ethnicity is required, but not both). Patients formerly coded as white and Hispanic are coded as Hispanic. Race and ethnicity sum to 100 percent. The categories are: Asian/Pacific Islander, Black, White, Hispanic/Latino, a combined group for other races, and Unknown is shown. Missing values were reported in the Unknown categories.  

Age
Age was determined as of the date of waitlist for each patient. The percentage of patients in each of several age ranges is reported.

Gender
The percentage of male and female candidates is reported.

Blood Type
The percentage of candidates by ABO type (O, A, B, AB) is reported. Candidates with ABO type A, A1, or A2 were classified as A. Candidates with ABO type AB, A1B, or A2B were classified as AB.

Previous Transplants
The percentage of candidates whose waitlist forms indicated that they had received any previous transplant is reported.

Peak Panel Reactive Antibody (Kidney, Pancreas, and Kidney/Pancreas Programs Only)
The candidates' highest panel reactive antibody (PRA) when placed on the waitlist is shown for candidates for kidney, pancreas, or kidney/pancreas transplant. The percentage of candidates in each of several PRA ranges (0-9, 10-79, 80+) is reported.

Primary Diagnosis Group (Not Shown for Pancreas and Kidney/Pancreas Programs)
The percentage of patients in each of the major categories of primary cause of organ failure is reported. The major categories for each organ are shown below. Primary diagnosis group is not shown for pancreas and kidney/pancreas programs because virtually all such patients receive a transplant for diabetes mellitus.

Kidney

• Glomerular diseases
• Tubular and interstitial disease
• Polycystic kidney disease
• Congenital, familial, and metabolic kidney diseases
• Diabetes mellitus
• Renovascular & vascular diseases
• Neoplasms
• Hypertensive nephrosclerosis
• Retransplant/graft failure
• Other kidney diseases
• Missing

Liver

• Acute hepatic necrosis
• Non-cholestatic cirrhosis
• Cholestatic liver disease/cirrhosis
• Biliary atresia
• Metabolic diseases
• Malignant neoplasms
• Other
• Missing

Intestine

• Short gut syndrome
• Functional bowel problem
• Retransplant/graft failure
• Other
• Missing

Heart

• Cardiomyopathy
• Coronary artery disease
• Retransplant/graft failure
• Valvular heart disease
• Congenital heart disease
• Other
• Missing

Lung

• Congenital disease
• Retransplant/graft failure
• Primary pulmonary hypertension
• Cystic fibrosis
• Idiopathic pulmonary fibrosis
• Alpha-1-antitrypsin deficiency
• Emphysema/Chronic obstructive pulmonary disease (COPD)
• Other
• Missing

Heart-Lung

• Congenital disease
• Retransplant/graft failure
• Primary pulmonary hypertension
• Cystic fibrosis
• Idiopathic pulmonary fibrosis
• Alpha-1-antitrypsin deficiency
• Emphysema/Chronic obstructive pulmonary disease (COPD)
• Other
• Missing

Years Since Diabetes Onset (Pancreas Programs Only)
The number of years since the onset of diabetes is reported.

Recipient Medical Urgency Status at Waitlist (Liver and Heart Programs Only)
The candidates' medical urgency status when registered on the waitlist is shown for liver and heart programs. The percentage of recipients in each of status type (Livers: Status 1, 2A, 2B, 3, Temporarily Inactive; Hearts: Status 1, 1A, 1B, 2, Temporarily Inactive) is reported.

Beginning on February 27, 2002 candidates for liver transplants were classified by MELD or PELD score rather than medical urgency status. However, Status 1 and "temporarily inactive" candidates were still grouped by their respective statuses. MELD and PELD scores were computed based on the candidates’ laboratory measures at the time of the wait listing. If not all of the necessary laboratory values were measured, the candidate was assigned a MELD or PELD of 6, depending on the candidate’s age. The following groups appear for liver candidates after February 27, 2002: Status 1, MELD 6-10, MELD 11-20, MELD 21-30, MELD 31-40, PELD 10 or less, PELD 11-20, PELD 21-30, PELD greater than 30, and Temporarily Inactive.

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Table 3. Transplant and Mortality Rates among Waitlist Patients

Table 3 reports transplant and mortality rates for patients on the waiting list between January 1, 2008 and December 31, 2009, along with the expected rates and corresponding p-values. For liver and kidney programs, there are two sets of transplant statistics: one for all transplant and another for transplants from deceased donors. Only transplants from deceased donors are included for other programs. The mortality rate statistics were designed to provide ascertainment of mortality once waitlisted instead of while waitlisted. In addition to deaths reported on the waitlist removals data forms, we have also included deaths from the Social Security Death Master File (SSDMF) and Centers for Medicare & Medicaid Services (CMS) data sources to provide additional death ascertainment for waitlisted patients through the end of the study. Thus, time at risk and mortality after removal from the waiting list for removals other than transplant, transfer, and recovery are included. The information in Table 3 is for all patients on the waitlist at this center at any time during the reported interval. Since patients are often listed for a pancreas for the purpose of maintaining vascular continuity when listed for a combined liver and intestine transplant, those candidates listed for a pancreas who are simultaneously on the intestine waiting list are excluded from all statistics in this table. For the purpose of comparison, corresponding rates for the second interval in this center's Donation Service Area and OPTN region as well as the United States as a whole are also reported.

Count on Waitlist at Start
The total number of patients on the waitlist at 12:00 am the morning of the beginning of the period is reported. Please note that counts in this table may be lower than similar counts in other waiting list tables, such as Table 1. A small percentage (~1%) of patients are found to have died or been transplanted before being removed from the waiting list, so these patients are excluded if the event occurs prior to the start of the study period.

Person Years for the Transplant Rate
Since candidates may be waitlisted for all or only part of a full year, person years of the patients on the waitlist for the whole period is reported. Person years are calculated as days and converted to fractional years for each patient. The number of days is calculated from the latter of the start date of the period and the date of first wait listing, until the earliest of the date of death, transplant, removal from the waitlist, or the end of the period. Also, time if a candidate becomes inactive on the waiting list, that time is still included. The person years for each candidate in the program are summed to yield the total person years.

Removals for transplant

The number of waitlist patients removed from the waitlist whose reason for waitlist removal was listed as receipt of a transplant during the period is reported.

Transplant Rate (per year on waitlist)
The rate shown is calculated by dividing the number of waitlist patients removed from the waitlist whose reason for waitlist removal was listed as receipt of a transplant by the total number of person years.

Expected Transplant Rate
The expected transplant rate is calculated as the number of waitlist patients expected to have been removed for receipt of a transplant divided by the number of person years. The expected number was calculated using a Cox proportional hazards model. Data for all organs were adjusted by age, blood type, days on the waiting list prior to the start date, and previous transplantation. Data for heart and liver are also adjusted by medical urgency status. Kidney data were also adjusted by peak PRA and the interaction between previous transplantation and peak PRA.

Beginning on February 27, 2002 candidates for liver transplants were classified by MELD or PELD score rather than medical urgency status. However, Status 1 and “temporarily inactive” candidates were still grouped by their respective statuses. In the transplant rate models, the match MELD/PELD score was used. This means that exceptions, such as those for Hepatocellular Carcinoma (HCC), were taken into account when granted. Some candidates that were Status 2A on 2/27/02 were left in that status for up to thirty more days, so they were grouped as Status 2A for the transplant rate model.

Ratio of Observed to Expected Transplants
For statistical comparisons, it is appropriate to compare the number of transplants observed during follow-up period to the number of transplants that would be expected during follow-up period. A ratio greater than 1.00 indicates that there were more transplants at the center than would have been expected based on the national experience, while a ratio less than 1.00 indicates that there were fewer transplants at the center than would have been expected based on the national experience. For example, a ratio of 1.20 indicates that the transplant rate at the center was, on average, 20% higher than the national rate. A ratio equal to 1.00 indicates that the transplant rates at the center are the same as the national transplant rates.

Random variation
The ratio reported is an estimate of the true ratio of transplant rates at the center relative to the national transplant rates. A ratio different from 1.00 indicates that the true transplant rates at the center differ from the national transplant rates. However, the value of the ratio varies from year to year above and below the true ratio due to random variation. Thus, the ratio could differ from 1.00 due to random variation, rather than due to a true difference between the transplant rates at the center and in the nation. Both the p-value and the confidence interval, discussed below, are designed to help in the interpretation of the ratio in the face of such random fluctuations.

95% Confidence Interval
The 95% confidence interval for the ratio of observed to expected transplants gives a range of plausible values for the true ratio of center to national transplant rates, in light of the observed ratio. The true ratio lies within this range 95% of the time. The confidence interval is a measure of how precisely we are able to estimate the ratio. If the 95% confidence interval includes 1.00, then the ratio is not significantly different than 1.00, which means that the transplant rates at the center are not significantly different than the national rates (p<0.05).

P-value

The p-value measures the statistical significance (or evidence) for testing the (two-sided) hypothesis that the difference between the actual and expected transplant rate is 0. A p-value less than or equal to 0.05 indicates that the difference between the actual and expected transplant rate is probably real and is not due to random chance, while a p-value greater than 0.05 indicates that the difference could plausibly be due to random chance. The p-value was calculated by testing whether the observed number of transplants was greater or less than the expected number of transplants at a center, based on the Poisson distribution for the observed number of failures. These values are not shown if there is no expected transplant rate calculated.

Note about one-sided vs. two-sided p-values:

The two-sided p-values presented in the CSRs are used to identify cases where observed transplant rates are statistically different from (either above or below) the expected rate. In other words, a two-sided p-value is used when the direction of the difference is not hypothesized. Since Program-Specific Reports are intended to measure a difference in either direction, a two-sided p-value is shown.

A one-sided p-value is used to test a hypothesis of a difference in a specific direction (e.g., lower than expected). To compute a one-sided p-value, divide the two-sided p-value in half, for the cases where the observed difference is in the hypothesized direction. For example, the MPSC uses a one-sided p-value to test the hypothesis that more deaths are observed than would be expected at a center. In this case, for a center with a two-sided p-value is 0.046 and observed death count exceeding the expected death count, the one-sided p-value would be 0.023.

How do rates at this center compare to those in the nation?

This line indicates whether the actual transplant rate is statistically different than the expected transplant rate based on the p-value on the previous line. If the p-value is less than or equal 0.05 then this line reads "Statistically Higher" or "Statistically Lower" depending on whether the actual transplant rate is higher or lower than the expected transplant rate. If the p-value is greater than 0.05 then this line reads "Not Significantly Different". These values are not shown if there is no expected transplant rate calculated.

Person Years for Mortality Rate after Being Placed on the Waitlist

Since candidates may be waitlisted for all or only part of a full year, person years of the patients on the waitlist for the whole period is reported. Person years are calculated as days and converted to fractional years for each patient. The number of days is calculated from the latter of the start date of the period and the date of first wait listing, until the earliest of the date of death, transplant, 60 days after removal for recovery, transfer, or the end of the period. Also, time if a candidate becomes inactive on the waiting list, that time is still included. The person years for each candidate in the program are summed to yield the total person years.

Number of deaths

The number of deaths that occurred among patients after being placed on the waitlist during the period is reported. Deaths reported on the waitlist removals data forms, the Social Security Death Master File (SSDMF) and Centers for Medicaid and Medicare Service (CMS) are included in this calculation.

Death Rate (per year on waitlist)
The rate shown is calculated by dividing the number of deaths by the number of person years.

Expected Death Rate
The expected death rate is calculated as the number of deaths expected to have occurred divided by the number of person years. The expected number was calculated using a Cox proportional hazards model. The expected death rates for all organs are adjusted by age, race, gender, blood type, days on the waiting list prior to the start date, and primary disease (except for pancreas and kidney/pancreas). The rates for heart and liver are also adjusted by medical urgency status.

Beginning on February 27, 2002 candidates for liver transplants were classified by MELD or PELD score rather than medical urgency status. However, Status 1 and "temporarily inactive" candidates were still grouped by their respective statuses. In the models for waitlist mortality, the MELD and PELD scores were computed based on the candidates’ laboratory measures for each point in time. If not all of the necessary laboratory values were measured, the candidate was assigned a MELD or PELD of 6, depending on the candidate’s age. Additionally, whether or not the MELD/PELD score was missing was adjusted for in the model.

Ratio of Observed to Expected Deaths

For statistical comparisons, it is appropriate to compare the number of deaths observed during follow-up period to the number of deaths or transplants that would be expected during follow-up period. A ratio greater than 1.00 indicates that there were more deaths at the center than would have been expected based on the national experience, while a ratio less than 1.00 indicates that there were fewer deaths at the center than would have been expected based on the national experience. For example, a ratio of 1.20 indicates that the death rate at the center was, on average, 20% higher than the national rate. A ratio equal to 1.00 indicates that the death rate at the center is the same as the national death rate.

Random variation

The ratio reported is an estimate of the true ratio of death rate at the center relative to the national death rate. A ratio different from 1.00 indicates that the true death rate at the center differ from the national death rate. However, the value of the ratio varies from year to year above and below the true ratio due to random variation. Thus, the ratio could differ from 1.00 due to random variation, rather than due to a true difference between the death rate at the center and in the nation. Both the p-value and the confidence interval, discussed below, are designed to help in the interpretation of the ratio in the face of such random fluctuations.

95% Confidence Interval

The 95% confidence interval for the ratio of observed to expected transplants gives a range of plausible values for the true ratio of center to national death rate, in light of the observed ratio. The true ratio lies within this range 95% of the time. The confidence interval is a measure of how precisely we are able to estimate the ratio. If the 95% confidence interval includes 1.00, then the ratio is not significantly different than 1.00, which means that the death rate at the center are not significantly different than the national rates (p<0.05).

P-value

The p-value measures the statistical significance (or evidence) for testing the (two-sided) hypothesis that the difference between the actual and expected death rate is 0. A p-value less than or equal to 0.05 indicates that the difference between the actual and expected death rate is probably real and is not due to random chance, while a p-value greater than 0.05 indicates that the difference could plausibly be due to random chance. The p-value was calculated by testing whether the observed number of deaths was greater or less than the expected number of deaths at a center, based on the Poisson distribution for the observed number of failures. These values are not shown if there is no expected death rate calculated.

Note about one-sided vs. two-sided p-values:

The two-sided p-values presented in the CSRs are used to identify cases where observed mortality rates are statistically different from (either above or below) the expected rate. In other words, a two-sided p-value is used when the direction of the difference is not hypothesized. Since Program-Specific Reports are intended to measure a difference in either direction, a two-sided p-value is shown.

A one-sided p-value is used to test a hypothesis of a difference in a specific direction (e.g., lower than expected). To compute a one-sided p-value, divide the two-sided p-value in half, for the cases where the observed difference is in the hypothesized direction. For example, the MPSC uses a one-sided p-value to test the hypothesis that more deaths are observed than would be expected at a center. In this case, for a center with a two-sided p-value is 0.046 and observed death count exceeding the expected death count, the one-sided p-value would be 0.023.

How do rates at this center compare to those in the nation?

This line indicates whether the actual death rate is statistically different than the expected death rate based on the p-value on the previous line. If the p-value is less than or equal 0.05 then this line reads "Statistically Higher" or "Statistically Lower" depending on whether the actual death rate is higher or lower than the expected death rate. If the p-value is greater than 0.05 then this line reads "Not Significantly Different". These values are not shown if there is no expected death rate calculated.

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Table 4. Waitlist Activity and Patient Vital Status at 6, 12, and 18 Months Since Waitlisting

Table 4 shows the status of waitlisted patients at three time points after waitlisting: 6, 12, and 18 months. Patients included are those who were put on the waitlist at this center between July 1, 2007 and June 30, 2008. For purposes of comparison, corresponding data for the U.S. are also reported at the same time points.

Patient waitlist status was determined by using waitlist removal codes. If a patient had not been removed from the waitlist at each time point they were considered to be alive on the waitlist. For patients whose removal codes corresponded to receiving a transplant, status was determined from follow-up records collected after the transplant. If a patient had a removal code for transplantation, but did not have any transplant or follow-up records on or after the given time point associated with that candidacy, they were placed under their appropriate transplant heading, subheading “status unknown.” In a small number of cases, a follow-up form will not have become due since the given time point and patients may appear as “status unknown” due to this timing issue.

Percentages indicated on the lines of the table above "TOTAL" (patients on the waitlist who are alive, have died, have been removed without transplant, have received living and deceased donor transplants, and are lost or transferred) add to 100% and reflect data from all patients waitlisted in during the period. It is important to note that these percentages reflect the full range of possible outcomes since placement on the waitlist. For example, if 3.5% died following deceased donor transplant at 18 months after waitlisting indicates that this percentage of all waitlisted candidates had received a deceased donor transplant and subsequently died by 18 months after waitlisting. A patient who falls into this category may have fallen into the category of living with a deceased donor transplant at an earlier time period.

The last four lines of the table contain summary death and transplant percentages. The total percent dead includes all patients reported to have died by that follow-up point, including those who die both before or after a transplant. The following line adds to this total those who were removed from the waitlist due to deteriorating medical condition, but were not reported as having died.

The total removed for transplant shows those patients listed as removed from the waiting list for transplant on or before this time, regardless of current status of the transplant. The last line shows the subset of these with whose transplant is still functioning at the point in time.

The death counts reported here include only those deaths reported as waitlist removals due to death or as deaths on transplant follow-up forms. These data sources are not designed to count all deaths, so the deaths reported here represent an under-ascertainment of mortality. Similarly, the graft failures reported here are based on transplant follow-up forms and do not include failures that occur after patients are reported as lost to follow-up.

For liver programs, additional tables provide the same data stratified by medical urgency status at listing.

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Table 5. Percent Transplanted (Excludes Living Donor Recipients) for Waitlist Patients at This Center

Table 5 gives the percentages of patients who received a transplant at the specified times (1 month, 1 year, 2 years, and 3 years after waitlisting) among those who were placed on the waitlist from Jan 1, 2004 - Dec 31, 2006. This information is given for the center and, for purposes of comparison, for the U.S. as a whole. The data exclude patients who were removed from the waitlist with a removal code indicating transplant from a living donor. Patients waitlisted for pancreatic islets are also excluded.

This analysis includes patients whose waitlist status was temporarily inactive and patients who spent periods of time in temporarily inactive status. The statistics are calculated as simple fractions and the analysis does not censor patients if they were removed for reasons other than receiving a transplant. Thus, patients who die before receiving a transplant are counted at all times as not having received a transplant. Each percentage is calculated among all patients and separately for different classifications of: race, ethnicity, age, gender, blood type, previous transplant, primary disease, peak PRA (kidney, pancreas, and kidney/pancreas programs only), years since diabetes onset (pancreas and kidney/pancreas programs only) and medical urgency status (heart and liver programs only).

The percentage shown is calculated as: 100  (number of patients placed on the waitlist between 1/1/2004 12:00:00 AM and 12/31/2006 12:00:00 AM who received a transplant prior to a specified number of months after waitlisting) / (total number of patients placed on the waitlist between 1/1/2004 12:00:00 AM and 12/31/2006 12:00:00 AM).

The national statistics double count patients with multiple listings in order to be comparable to the center statistic, which counts each waitlist at the center, but only the transplant at this center.

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Table 6. Time to Transplant for Waitlist Candidates

Table 6 gives the median (50th percentile) waiting time until transplant (both deceased donor and living related transplants) for patients who were placed on the waitlist between January 1, 2004 and June 30, 2009, as well as the 5th, 10th, 25th and 75th percentile waiting times. All percentiles are shown only when applicable. The information in this table is for all patients placed on the waitlist at this center during the applicable time period. For purposes of comparison, corresponding times to transplant at each percentile in this center's OPTN region and the U.S. as a whole are also reported. Patients with multiple waitlistings are counted multiple times in this analysis.

Waiting time until transplant is calculated as the time (in months) after a candidate is placed on the waitlist, by which the corresponding percent of all patients initially waitlisted had been removed from the waitlist for receiving a transplant. A Kaplan-Meier model was used with censoring on a) December 31, 2009 for those registrations still waiting on that date; and b) the date of removal from the waiting list for recovery, or c) the date of removal from the waiting list for a transfer. If a cell is blank then less than that percentage of patients placed had received a transplant by the end of follow-up.

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Table 7. Transplant Recipient Characteristics

Table 7 summarizes the characteristics of transplant recipients who received a transplant between January 1, 2009 and December 31, 2009 at this center, with corresponding average values among recipients in this center's OPTN region and the U.S. as a whole. Table 7 is divided into deceased donor and living donor transplants for kidney, liver and lung programs. For all other programs, only data for deceased donor transplants are shown. The percentages are reported for each characteristic. The percentages within each characteristic add to 100% except for rounding anomalies. Candidates with missing information are in the "Unknown" or "Missing" categories.

Patient Count
The total numbers of patients who received transplants during this period at this center, in this center's OPTN region, and in the U.S. as a whole are reported. The summaries of the patient characteristics in Table 7 are based on the patient population counts.

Race
The percentage of recipients in each of five race categories is reported. Race and ethnicity are reported together as a single data element, reflecting their data collection (either race or ethnicity is required, but not both). Patients formerly coded as white and Hispanic are coded as Hispanic. Race and ethnicity sum to 100 percent. The categories are: Asian/Pacific Islander, Black, White, Hispanic/Latino, a combined group for other races, and Unknown is shown. Missing values were reported in the Unknown category. 

Age
Age was determined as of the date of transplant for each patient. The percentage of recipients in each of several age ranges is reported.

Gender
The percentage of male and female recipients is reported.

Blood Type
The percentage of recipients by ABO type (O, A, B, AB) is reported. Recipients with ABO type A, A1, or A2 were classified as A. Recipients with ABO type AB, A1B, or A2B were classified as AB.

Previous Transplants
The percentage of recipients who previously received any organ transplant is shown.

Peak Panel Reactive Antibody (Kidney, Pancreas and Kidney/Pancreas Programs Only)
The recipients' highest panel reactive antibody (PRA) on the waitlist is shown for recipients who received a kidney, pancreas, or kidney/pancreas. The percentage of recipients in each of several PRA ranges (0-9, 10-79, 80+) is reported.

Body Mass Index
Body mass index is calculated at transplant as the recipient's weight divided by the height squared (BMI = Weight (kg)/ Height2 (m2)). The percentage of recipients in each of several BMI ranges (0-20, 21-25, 26-30, 31+) is reported.

Primary Diagnosis Group (Not Shown for Pancreas and Kidney/Pancreas Programs)
The percentage of patients in each of the major categories of primary cause of organ failure is reported. The major categories for each organ are shown below. Primary diagnosis group is not shown for pancreas and kidney/pancreas programs because virtually all such patients received a transplant for diabetes mellitus.

Kidney

• Glomerular diseases
• Tubular and interstitial disease
• Polycystic kidney disease
• Congenital, familial, metabolic renal diseases
• Diabetes mellitus
• Renovascular & vascular diseases
• Neoplasms
• Hypertensive nephrosclerosis
• Retransplant/graft failure
• Other kidney diseases
• Missing

Liver

• Acute hepatic necrosis
• Non-cholestatic cirrhosis
• Cholestatic liver disease/cirrhosis
• Biliary atresia
• Metabolic diseases
• Malignant neoplasms
• Other
• Missing

Intestine

• Short gut syndrome
• Functional bowel problem
• Retransplant/graft failure
• Other
• Missing

Heart

• Cardiomyopathy
• Coronary artery disease
• Retransplant/graft failure
• Valvular heart disease
• Congenital heart disease
• Other
• Missing

Lung

• Congenital disease
• Retransplant/graft failure
• Primary pulmonary hypertension
• Cystic fibrosis
• Idiopathic pulmonary fibrosis
• Alpha-1-antitrypsin deficiency
• Emphysema/Chronic obstructive pulmonary disease (COPD)
• Other
• Missing

Heart-Lung

• Congenital disease
• Retransplant/graft failure
• Primary pulmonary hypertension
• Cystic fibrosis
• Idiopathic pulmonary fibrosis
• Alpha-1-antitrypsin deficiency
• Emphysema/Chronic obstructive pulmonary disease (COPD)
• Other
• Missing

Recipient Medical Urgency Status at Waitlist (Liver and Heart Programs for Patients with Deceased Donors Only)
The recipients' medical urgency status when registered on the waitlist is shown for liver and heart programs. The percentage of recipients in each of status type (Livers: Status 1, 2A, 2B, 3, Temporarily Inactive; Hearts: Status 1, 1A, 1B, 2, Temporarily Inactive) is reported.

Recipient Medical Urgency Status at Transplant (Liver and Heart Programs for Patients with Deceased Donors Only)
The recipients' medical urgency status at the time of transplant is shown for liver and heart programs. The percentage of recipients in each of status type (Livers: Status 1, 2A, 2B, 3, Temporarily Inactive; Hearts: Status 1, 1A, 1B, 2, Temporarily Inactive) is reported.

Beginning on February 27, 2002 candidates for liver transplants were classified by MELD or PELD score rather than medical urgency status. However, Status 1 and "temporarily inactive" candidates were still grouped by their respective statuses. MELD and PELD scores were computed based on the candidates’ laboratory measures at the time of transplant. The following groups appear for liver recipients after February 27, 2002: Status 1, MELD 6-10, MELD 11-20, MELD 21-30, MELD 31-40, PELD 10 or less, PELD 11-20, PELD 21-30, PELD greater than 30, and Temporarily Inactive.

Recipient Medical Condition at Transplant
The medical condition of the recipient at transplant is shown. The percentage of recipients in each of 3 conditions (In ICU, Hospitalized, Not Hospitalized) is reported. The percentage without a condition reported is also shown.

Recipient Life Support Status at Transplant
The type of life support at transplant is shown for heart transplant recipients. Life support status is divided into three groups: no life support, devices (including ventricular assist devices (VAD), extracorporeal membrane oxygenation (ECMO), intraaortic balloon pump (IABP), and total artificial heart (TAH)), and other life support. The percentage without a status reported is also displayed.

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Table 8. Summary for Characteristics of Transplant Donors

Table 8 summarizes the characteristics of living (kidney, liver and lung only) and deceased transplant donors who donated an organ between January 1, 2009 and December 31, 2009 in this center, with corresponding average values among donors in this center's OPTN region and the U.S. as a whole. Only donors whose organs were transplanted to recipients at this center, in this center's OPTN region, and the U.S. as a whole are counted.

Patient Count
The total number of organ donors whose donated organs were of the type corresponding to this center's program and that were transplanted during this period at this center is reported. The summaries of the donor characteristics in Table 8 are based on the patient population count.

Cause of Death
For deceased donors, the percentage of organs recovered and transplanted from donors in each of the major cause of death categories is reported. The categories for cause of death are Stroke, Motor Vehicle Accident (MVA), and Other.

Age
Donor age was determined as of the date of organ procurement for each donor. The percentage of donors in each of several age ranges is reported.

Race
The percentage of transplant donors in each of five race categories is reported. Race and ethnicity are reported together as a single data element, reflecting their data collection (either race or ethnicity is required, but not both). Patients formerly coded as white and Hispanic are coded as Hispanic. Race and ethnicity sum to 100 percent. The categories are: Asian/Pacific Islander, Black, White, Hispanic/Latino, a combined group for other races, and Unknown is shown. Missing values were reported in the Unknown category.   

Gender
The percentage of male and female donors is reported.

Blood Type
The percentage of donors by ABO type (O, A, B, AB) is reported. Donors with ABO type A, A1, or A2 were classified as A. Donors with ABO type AB, A1B, or A2B were classified as AB.

Expanded Criteria Donors
The percentage of donors (for kidney programs only) by whether or not they met the expanded donor criteria is reported. Donors that meet the expanded criteria are those over 60 years of age and those between 50 and 59 years of age meeting two of the following three conditions: died of a stroke, had a history of hypertension, or had a serum creatinine of greater than 1.5.

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Table 9. Summary for Characteristics of Transplant Operations

Table 9 summarizes the characteristics of deceased donor transplants performed between  January 1, 2009 and December 31, 2009 at this center, with corresponding average values for transplants performed in this center's OPTN region and the U.S. as a whole. For kidney, liver and lung programs, a comparable table summarizing characteristics of living donor transplant operations is also provided.

Patient Count
The total numbers of deceased donor transplants during this period at this center, in this center's OPTN region, and the U.S. as a whole are reported. For kidney and liver programs, the total number of living donor transplants during this period at this center, in this center's OPTN region, and the U.S. as a whole are reported. The summaries of the transplant characteristics in Table 9 are based on the patient population count.

Cold Ischemic Time (Deceased Donor Transplants Only)
The percent of transplants that fall into each category of cold ischemic time are reported by whether the donated organ was procured locally or from outside the OPO (see Sharing below). This time is divided into 90-minute increments for thoracic transplants, and by ranges of hours for the other organs.

Relation With Donor (Living Donor Transplants Only)
The percent of transplants whose living donor was biologically related (Related), such as sibling, parent or other family member, and biologically unrelated (Unrelated), such as spouse, anonymous donor or organ exchange, are reported. The percent of transplants where the relation is unknown (Not Reported) is also given.

Level of Mismatch
Level of HLA mismatch (0-6) is calculated by comparing antigen values for the A, B and DR loci between donors and their respective recipients, accounting for known antigen splits. The number of mismatches is derived by subtracting the number of matches and missing donor values from the number of potential matches (six).

Procedure Type
The procedure type, meaning whether the organ was transplanted alone or with other organs, is shown. For kidney/pancreas programs, organs in addition to a kidney and pancreas are included in the 'Multi-Organ' column.

Dialysis in First Week After Transplant
The percentage of patients who received dialysis treatment within one week following transplant is shown. This is only shown for kidney recipients.

Sharing (Deceased Donor Transplants Only)
Shown are the percent of transplants for which the organ was procured outside the center's OPO (shared) and the percent of transplants where the organs were procured from within the center's OPO (local).

Median Length of Stay
Shown is the actual number of days the patient remained in the hospital following receipt of a transplant. If a patient receives multiple transplants of the same organ during the same hospital stay, the number of days is from the first transplant until the final discharge date. Multiple organ transplants are excluded from this statistic in most cases. The kidney-pancreas and heart-lung tables include only kidney-pancreas or heart-lung transplants, but not other multi-organ transplants.

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Table 10. Graft Survival Rates

Table 10 reports graft survival (the fraction of patients alive with grafts that are still functioning) at several time points after transplantation. Graft survival is reported at the 1-month, 1-year, and 3-year reporting time points for each center, with corresponding rates for the U.S. Only those transplants that occurred between July 1, 2004 and June 30, 2009 were eligible for inclusion in the analyses. For the 1-month and 1-year statistics, transplants occurring between January 1, 2007 and June 30, 2009 were included. Transplants that occur during the last 6 months of this cohort have only 6 months of follow-up available but can be included using censored data methods (described below) in the 1-year statistics. For the 3-year survival statistics, transplants that occurred between July 1, 2004 and December 31, 2006 were included.

Statistics are reported separately for adult (age 18 and older) and pediatric (age less than 18) patients. In addition, statistics are reported separately by donor type (deceased and living) for kidney and liver programs. There are some organs or subgroups of patients for which there are too few transplants or too few events to calculate meaningful statistics. The table below indicates which statistics are calculated for each organ.

Not all transplant recipients had complete graft survival through the end of the time interval since transplant. However, all available follow-up data for each graft were used in the calculation of the statistics reported here using standard censored data methods of survival analysis (Cox 1972, Kaplan-Meier 1958). Additional data from the Social Security Death Master File (SSDMF) have been incorporated into the graft survival rates.

Statistics Reported in Graft Survival Table (Table 10) by Organ
	Counts of Transplants and Actual1 Graft Survival		Expected2 Graft Survival
ORGAN	Age 18+	Age 18<	Age 18+	Age 18<
Heart	Yes	Yes	Yes	Yes
Heart-Lung	Yes	No	No	No
Lung	Yes	Yes	Yes	No
Liver	Yes	Yes	Yes	Yes
Kidney	Yes	Yes	Yes	Yes
Intestine	Yes	Yes	No	No
Pancreas	Yes	No	No	No
Kidney from a Kidney-Pancreas	Yes	No	Yes	No
Pancreas from a Kidney-Pancreas	Yes	No	Yes	No
1 Graft survival was estimated using the Kaplan-Meier methodology to allow inclusion of patients with incomplete follow-up. 2 Expected graft survival is based on data from the entire nation to evaluate the survival expected for the patients at each center, based upon their characteristics.

Number of Transplants
The total number of transplants reported during the accrual periods for the 1-month, 1-year and 3-year graft survival analyses are shown for each patient age cohort. The 1-month and 1-year counts are the same since the accrued periods are the same.

Living donor transplants are included only for kidneys and livers. The heart, lung, liver, kidney, and pancreas tables include only single-organ transplants. The kidney-pancreas and heart-lung tables include only kidney-pancreas or heart-lung transplants, but not other multi-organ transplants. The intestine tables include single-organ intestine, liver-intestine, pancreas-intestine, and pancreas-liver-intestine transplants. Heterotopic heart and liver transplants are not included.

Graft Survival
Graft failure is defined differently for different organs. For all organs, deaths are considered to be graft failures. Once the patient has died, it cannot be determined how long the graft would have functioned had the patient lived. The SSDMF is used in conjunction with OPTN data to identify deaths. In the case of conflicting deaths dates from various sources, the OPTN death date takes precedence. If there is no OPTN death date but conflicting dates from SSDMF and CMS, the SSDMF date takes precedence.

A graft is counted as failed when follow-up information indicates that one of the following has occurred prior to the reporting time point: graft failure (except for heart and liver where retransplant dates are used instead), retransplant (all but heart-lung and lung), or death. OPTN follow-up forms are used to identify graft failure and retransplant dates.

Transplants that occurred in the last six months of the accrual period for the 1-year reporting time point are only followed for six months after transplant because the 1-year follow-up information is not yet available in the current OPTN data. The reporting time point for this subset of transplants is six months after transplantation.

The "Graft Survival" at 1 month, 1 year and 3 years was calculated from the follow-up data using the Kaplan-Meier (KM) method and is an estimate of the fraction of all grafts that would still be functioning at the reporting time point had they been followed to that time. The KM method uses all data, including the incomplete data for patients who were lost before the end of the period. The KM method assumes that the failure rate would be the same for those patients lost to follow-up as was observed for those with complete data.

Lung, Heart-Lung, Kidney, Pancreas, Kidney-Pancreas, Intestine

For these organs, after a patient was recorded as lost to follow-up on one follow-up record, any subsequent follow-up records were disregarded. These calculations do not include any deaths that occur after loss to follow-up in the OPTN database, because the date of graft failure is unknown in these cases and may have occurred before the death.

For lung and heart-lung transplants, patients are followed until graft failure or death, with follow-up censored at the last OPTN follow-up date. If the patient dies before the last OPTN follow-up, the death date is used as the graft failure date. Deaths after this date are not included in the analyses.

For kidney, pancreas, kidney-pancreas, and intestine transplants, patients are followed under graft failure, retransplant, or death, with follow-up again censored at the last OPTN follow-up date. If the patient dies or is retransplanted before the last OPTN follow-up, the death or retransplant date is used as the graft failure date. Deaths or retransplants after this date are not included in the analyses.

Transplants with a graft failure date recorded as having occurred prior to the transplant and transplants with no follow-up forms, missing last follow-up date or last follow-up date before the transplant were analyzed as censored (lost to follow-up) on the day of transplant. This means they do not affect the reported results and they are included only to retain consistency with the reported number of transplants. Transplants with no follow-up forms will influence the statistics related to follow-up days reported (described elsewhere).

Heart and Liver

For the heart and liver analyses, there is no need for extra ascertainment of graft failure after the last OPTN follow-up date because there is no alternative therapy. A patient whose graft fails will be retransplanted or die. The calculations of graft failure therefore can continue until the reporting time pointtime-point even if the recipient is lost to follow-up in the OPTN data. Accordingly, for heart and liver transplants, follow-up for graft survival is not censored at the last OPTN follow-up date and the OPTN graft failure date is not used. Instead, only deaths and retransplants are used as graft failure dates.

Expected Graft Survival
The "Expected Graft Survival" is the fraction of grafts that would be expected to be functioning at each reported time point, based on the national experience for patients similar to those at this center. The "Graft Survival" can be compared to the "Expected Graft Survival" as the percent of grafts functioning at the reporting time points. If the "Graft Survival" is greater than the "Expected Graft Survival", then the graft survival is better at this center than would be expected based on the national transplant experience for similar grafts and patients.

The national experience was analyzed using data for all grafts at all facilities in the United States. A Cox proportional hazards regression model for time to graft failure (Cox 1972) was fitted to the national data, which yielded the probability of graft failure for each patient, based upon the characteristics of each patient and the reporting time point. The expected survival is the average of these computed probabilities. The characteristics accounted for in these calculations are reported below and are similar to those that have been used in previous reports. Models are fit separately by age group (adult and pediatric) and cohort (1-month/1-year and 3-year). For kidney and liver transplants, models are also fit separately for living and deceased donor transplants. The "Expected Graft Survival" for each organ was adjusted for the patient characteristics as listed in the Risk-Adjustment Models. See Section XII for details on the calculation of the expected graft survival.

Ratio of Observed to Expected Graft Failures
For statistical comparisons, it is appropriate to compare the number of graft failures observed during follow-up (which is shorter than the reporting time point for censored patients) to the number of graft failures that would be expected during follow-up, rather than comparing observed and expected survival rates at the reporting time points. The ratio of observed to expected graft failures compares the entire survival curve up to the reporting time point to the curve expected for patients with the same characteristics based on the national experience rather than just the survival at the reporting time point. A ratio greater than 1.00 indicates that there were more graft failures at the center than would have been expected based on the national experience, while a ratio less than 1.00 indicates that there were fewer graft failures at the center than would have been expected based on the national experience. For example, a ratio of 1.20 indicates that the graft failure rate at the center was, on average, 20% higher than the national rate. A ratio equal to 1.00 indicates that the graft failure rates at the center are the same as the national graft failure rates.

Random variation

The ratio reported is an estimate of the true ratio of graft failure rates at the center relative to the national graft failure rates. A ratio different from 1.00 indicates that the true graft failure rates at the center differ from the national graft failure rates. However, the value of the ratio varies from year to year above and below the true ratio due to random variation. Thus, the ratio could differ from 1.00 due to random variation, rather than due to a true difference between the andgraft failure rates at the center and in the nation. Both the p-value and the confidence interval, discussed below, are designed to help in the interpretation of the ratio in the face of such random fluctuations.

95% Confidence Interval

The 95% confidence interval for the ratio of observed to expected graft failures gives a range of plausible values for the true ratio of center to national graft failure rates, in light of the observed ratio. The true ratio lies within this range 95% of the time. The confidence interval is a measure of how precisely we are able to estimate the ratio. If the 95% confidence interval includes 1.00, then the ratio is not significantly different than 1.00, which means that the graft failure rates at the center are not significantly different than the national rates (p<0.05).

P-value

The p-value measures the statistical significance (or evidence) for testing the (two-sided) hypothesis that the true ratio of graft failure rates for the center versus the nation equals 1.00. A smaller p-value tends to occur when the ratio differs more greatly from 1.00 and when more patient data are used to calculate the ratio. A p-value less than 0.05 is often taken as evidence that the ratio of graft failure rates truly differs from 1.00. Thus, a p-value less than 0.05 indicates that the difference between the graft failure rates at the center and the nation is unlikely to have arisen from random fluctuations alone. The smaller the p-value, the more statistically significant is the difference between the national and the center graft failure rates. A small p-value helps to rule out the possibility that the difference of the ratio from 1.00 could have arisen by chance. However, a small p-value does not indicate whether or not the magnitude of the difference between the death rates at the center and the nation is important. The actual quantitative value of the ratio reflects the clinical importance of the difference between the center and national graft failure rates. A ratio that differs greatly from 1.00 is more important while a ratio in the range 0.95 to 1.05 is not as important.

The p-value was calculated by testing whether the observed number of graft failures was statistically greater or less than the expected number of graft failures at a center, based on the Poisson distribution for the observed number of graft failures. The p-value is not shown if the expected graft survival was not calculated.

Note about one-sided vs. two-sided p-values:

The two-sided p-values presented in the CSRs are used to identify cases where observed graft failure rates are statistically different from (either above or below) the expected rate. In other words, a two-sided p-value is used when the direction of the difference is not hypothesized. Since Program-Specific Reports are intended to measure a difference in either direction, a two-sided p-value is shown.

A one-sided p-value is used to test a hypothesis of a difference in a specific direction (e.g., lower than expected). To compute a one-sided p-value, divide the two-sided p-value in half, for the cases where the observed difference is in the hypothesized direction. For example, the MPSC uses a one-sided p-value to test the hypothesis that more graft failures are observed than would be expected at a center. In this case, for a center with a two-sided p-value is 0.046 and observed graft failure count exceeding the expected graft failure count, the one-sided p-value would be 0.023.

How do the rates at this center compare to those in the nation?

This line indicates whether the actual graft survival is statistically different than the expected graft survival based on the p-value on the previous line. If the p-value is less than or equal 0.05 then this line reads "Statistically Higher" or "Statistically Lower" depending on whether the actual graft survival is higher or lower than the expected graft survival. "Statistically Higher" survival corresponds to better outcomes (ratios less than 1.00), while "Statistically Lower" survival corresponds to worse outcomes (ratios greater than 1.00). If the p-value is greater than 0.05 then this line reads "Not Significantly Different". This value is not shown if the expected graft survival is not calculated.

Follow-Up Days Reported

This line reports the percentage of days that are targeted for inclusion during the follow-up period relative to the number of days that were actually reported with OPTN transplant follow-up forms. As described above, heart and liver statistics include follow-up days after the last transplant follow-up form based on information from other OPTN data (such as subsequent transplants or waitlist information), the SSDMF, or CMS. These days are not included in this percentage even though they are included in the analyses. This means that the follow-up statistic has a different interpretation for heart and liver tables than for other organs (described in more detail below). For all organs, the percentage of follow-up days reported gives a measure of the amount of time for which we have follow-up from the center itself.

For grafts that did not fail before the end of the period, the targeted number of days of follow-up is the entire period (30, 365 or 1096 days; see next section for details on maximum follow-up). For grafts transplanted during the last 6 months of the period, the targeted follow-up for 1 year survival is 6 months. For grafts that failed before the end of the period, the number of targeted days of follow-up is the number of days until graft failure. The number of days of reported follow-up is less than the targeted number of days for censored patients. Examples are shown in the table below. The total number of days of follow-up reported for all patients are summed and divided by the total number of days of follow-up targeted to obtain the percent reported in this line.

Examples of incomplete follow-up and the calculation of the percent of follow-up reported are shown in the table below.

For lung, heart-lung, kidney, pancreas, kidney-pancreas, and intestine statistics, patients with incomplete follow-up are included in the analyses until the date of the last reported follow-up. For these organs, the percent of follow-up days reported is a measure of the presence of incomplete, or censored, data. Censored data reduces the precision and interpretability of the statistics reported here. A low percent of follow-up days reported may indicate a non-random sample from the center for follow-up and the graft survival reported may not be a reliable estimate of the true graft survival for the time period.

For liver and heart statistics, follow-up for graft survival is not censored at the last OPTN follow-up date for any patients. The calculation of the number of follow-up days reported in this row for liver and heart is the same as for the other organs however. The difference is in the interpretation of the statistic: for the liver and heart statistics, the follow-up percent does not measure the amount of censoring in the data, but instead is a measure of how dependent the results are on outside there may be under-ascertainment of graft failure for the facility since the completeness of follow-up data is still partially determined by center reporting.

Examples of incomplete follow-up and calculations of follow-up days reported
Transplant Date	Last Report	Reporting Time Point	Follow-Up Time	Graft Status	Follow-Up Reported (%)
7/1/98	3/1/99	30 days	30 days	Functioning	100%
7/1/98	3/1/99	1 year (365 days)	244 days	Functioning (Pt Censored)	67%
7/1/96	7/1/97	3 years (1096 days)	367 days	Failed Dead	100%
7/1/96	7/1/97	3 years (1096 days)	367 days	Functioning (Pt Censored)	35%

Maximum Days of Follow-Up
Patients were followed for up to 30 days for the 1-month statistics, up to 365 days for the 1-year statistics and up to 1096 days for the 3-year statistics starting at the day of transplant (day 1). The maximum follow-up time for patients in the center is reported on this line. If this maximum is less than 30 days for the 1-month, 365 for the 1-year or 1096 for the 3-year statistics, then the graft survival reported is not a reliable estimate of the true graft survival for the time period.

Review Criteria (preview site only)
This section contains information used by the OPTN Membership and Professional Standards Committee (MPSC) to flag centers for review: (1) Observed/Expected greater than 1.5, (2) Observed minus Expected greater than 3, (3) one-sided P-value less than 0.05; an additional row indicates whether the center has been flagged for each survival cohort. This section is for each center’s information and review and will not appear on the public version of the reports.

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Table 11. Patient Survival Rates

Table 11 reports patient survival (the fraction of patients that are still alive) at several time points after first transplantation for this organ. Patient survival is reported at the 1-month, 1-year, and 3-year reporting time points for each center, with corresponding rates for the U.S. Only those transplants that occurred between July 1, 2004 and June 30, 2009 were eligible for inclusion in the analyses. For the 1-month and 1-year statistics, transplants that occurred between January 1, 2007 and June 30, 2009 were included. Transplants which occur during the last 6 months of this cohort have only 6 months of follow-up available but can be included using censored data methods (described below) in the 1-year statistics. For the 3-year survival statistics, transplants that occurred between July 1, 2004 and December 31, 2006 were included. Table 11 includes all patients who received their first transplant of this organ type during the accrual period. Patients who had previously received a transplant of this type, whether this previous transplant occurred during the accrual period or not, were not included. For this reason, the patient count in Table 11 may be smaller than the transplant count in Table 10.

Statistics are reported separately for adult (age 18 and older) and pediatric (age less than 18) patients. In addition, statistics are reported separately by donor type (deceased and living) for kidney and liver programs. There are some organs or subgroups of patients for which there were too few transplants or too few events to calculate meaningful statistics. The table below indicates which statistics are calculated for each organ.

Additional data from the Social Security Death Master File (SSDMF) have been incorporated into the patient survival rates. The SSDMF data are used in conjunction with OPTN data to determine whether each patient is alive at the end of the follow-up period. If the patient is not reported to have died in either source, the patient is assumed to be alive.

Statistics Reported in Patient Survival Table (Table 11) by Organ
	Counts of Transplants and Actual1 Patient Survival		Expected2 Patient Survival
ORGAN	Age 18+	Age 18<	Age 18+	Age 18<
Heart	Yes	Yes	Yes	Yes
Heart-Lung	Yes	No	No	No
Lung	Yes	Yes	Yes	No
Liver	Yes	Yes	Yes	Yes
Kidney	Yes	Yes	Yes	No
Intestine	Yes	Yes	No	No
Pancreas	Yes	No	No	No
Kidney-Pancreas	Yes	No	Yes	No
1 Patient survival was estimated using the Kaplan-Meier methodology to allow inclusion of patients with incomplete follow-up. 2 Expected patients survival is based on data from the entire nation to evaluate the survival expected for patients at each center, based upon their characteristics.

Number of Patients
The total number of patients reported to have received their first transplant of the organ type during the accrual periods for the 1-month, 1-year and 3-year patient survival analyses are shown for each patient age cohort. The 1-month and 1-year counts are the same since the accrued periods are the same. Note that this line reports counts of patients rather than transplants and therefore will not be the same as the count of transplants in Table 10.

Patients receiving living donor transplants are included only for kidneys and livers. The heart, lung, liver, kidney, and pancreas tables include only patients receiving single-organ transplants. The kidney-pancreas and heart-lung tables include only patients receiving kidney-pancreas or heart-lung transplants, not other multi-organ transplants . The intestine tables include patients receiving single-organ intestine, liver-intestine, pancreas-intestine, or pancreas-liver-intestine transplants, but not other multi-organ transplants. Patients receiving heterotopic heart and liver transplants are not included.

Patient Survival

A patient is counted as having died when OPTN follow-up information, SSDMF data, or CMS data indicates that a death has occurred prior to the reporting time point. In the case of conflicting deaths dates from various sources, the OPTN death date takes precedence. If there is no OPTN death date but conflicting dates from SSDMF and CMS, the SSDMF date takes precedence. If the patient is not reported to have died in any source, the patient is assumed to be alive.

Patients who are transplanted in the last six months of the accrual period for the 1-year reporting time point are only followed for six months after transplant because the 1-year follow-up information is not yet available in the current OPTN data. The reporting time point for this subset of patients is six months after transplantation.

The follow-up time for each patient (days at risk) is the number of days from transplantation until death or the reporting time point (e.g., 1 month, 1 year, or 3 years) occurs, whichever is earliest. The "Patient Survival" at 1 month, 1 year and 3 years was calculated using the Kaplan-Meier (KM) method. It is an estimate for the fraction of all accrued patients who would still be alive at the reporting time point had they been followed to that time.

Expected Patient Survival

The "Expected Patient Survival" is the fraction of patients who would be expected to be alive at each reported time point, based on the national experience for patients similar to those at this center. The "Patient Survival" can be compared to the "Expected Patient Survival" as the percent alive at the reporting time points. If the "Patient Survival" is greater than the "Expected Patient Survival", then the patient survival is better at this center than would be expected based on the national transplant experience for similar patients.

The national experience was analyzed using data for all accrued transplants at all facilities in the United States. A Cox proportional hazards regression model for time to death (Cox 1972) was fitted to the national data, which yielded the probability of survival to the reporting time point for each patient, based upon the characteristics of each patient and the reporting time point. The expected survival is the average of these computed probabilities. The characteristics accounted for in these calculations are reported below and are similar to those that have been used in previous reports. Models are fit separately by age group (adult and pediatric) and cohort (1-month/1-year and 3-year). For kidney and liver transplants, models are also fit separately for living and deceased donor transplants. The "Expected Patient Survival" for each organ was adjusted for the patient characteristics as listed in the Risk-Adjustment Models. See Section XII for details on the calculation of the expected patient survival.

Ratio of Observed to Expected Deaths

For statistical comparisons, it is appropriate to compare the number of deaths observed during follow-up (which is shorter than the reporting time point for censored patients) to the number of deaths that would be expected during follow-up, rather than by comparison of observed and expected survival rates at the reporting time points. The ratio of observed to expected deaths compares the entire survival curve up to the reporting time point to the curve expected for patients with the same characteristics based on the national experience rather than just the survival at the reporting time point. A ratio greater than 1.00 indicates that there were more deaths at the center than would have been expected based on the national experience, while a ratio less than 1.00 indicates that there were fewer deaths at the center than would have been expected based on the national experience. For example, a ratio of 1.20 indicates that the death rate at the center was, on average, 20% higher than the national rate. A ratio equal to 1.00 indicates that the death rates at the center are the same as the national death rates.

Random variation

The ratio reported is an estimate of the true ratio of death rates at the center relative to the national death rates. A ratio different from 1.00 indicates that the true death rates at the center differ from the national death rates. However, the value of the ratio varies from year to year above and below the true ratio due to random variation. Thus, the ratio could differ from 1.00 due to random variation, rather than due to a true difference between the death rates at the center and in the nation. Both the p-value and the confidence interval, discussed below, are designed to help in the interpretation of the ratio in the face of such random fluctuations.

95% Confidence Interval

The 95% confidence interval for the ratio of observed to expected deaths gives a range of plausible values for the true ratio of center to national death rates, in light of the observed ratio The true ratio lies within this range 95% of the time. The confidence interval is a measure of how precisely we are able to estimate the ratio. If the 95% confidence interval includes 1.00, then the ratio is not significantly different than 1.00, which means that the death rates at the center are not significantly different than the national rates (p<0.05).

P-value

The p-value measures the statistical significance (or evidence) for testing the (two-sided) hypothesis that the true ratio of death rates for the center versus the nation equals 1.00. A smaller p-value tends to occur when the ratio differs more greatly from 1.00 and when more patient data are used to calculate the ratio. A p-value less than 0.05 is often taken as evidence that the ratio of death rates truly differs from 1.00. Thus, a p-value less than 0.05 indicates that the difference between the death rates at the center and the nation is unlikely to have arisen from random fluctuations alone. The smaller the p-value, the more statistically significant is the difference between the national and the center death rates. A small p-value helps to rule out the possibility that the difference of the ratio from 1.00 could have arisen by chance. However, a small p-value does not indicate whether or not the magnitude of the difference between the death rates at the center and the nation is important. The actual quantitative value of the ratio reflects the clinical importance of the difference between the center and national death rates. A ratio that differs greatly from 1.00 is more important while a ratio in the range 0.95 to 1.05 is not as important.

The p-value was calculated by testing whether the observed number of deaths was statistically greater or less than the expected number of deaths at a center, based on the Poisson distribution for the observed number of deaths. The p-value is not shown if the expected graft survival was not calculated.

Note about one-sided vs. two-sided p-values:

The two-sided p-values presented in the CSRs are used to identify cases where observed death rates are statistically different from (either above or below) the expected rate. In other words, a two-sided p-value is used when the direction of the difference is not hypothesized. Since Program-Specific Reports are intended to measure a difference in either direction, a two-sided p-value is shown.

A one-sided p-value is used to test a hypothesis of a difference in a specific direction (e.g., lower than expected). To compute a one-sided p-value, divide the two-sided p-value in half, for the cases where the observed difference is in the hypothesized direction. For example, the MPSC uses a one-sided p-value to test the hypothesis that more deaths are observed than would be expected at a center. In this case, for a center with a two-sided p-value is 0.046 and observed death count exceeding the expected graft failure count, the one-sided p-value would be 0.023.

How do the rates at this center compare to those in the nation?

This line indicates whether the actual patient survival is statistically different than the expected patient survival based on the p-value on the previous line. If the p-value is less than or equal 0.05 then this line reads "Statistically Higher" or "Statistically Lower" depending on whether the actual patient survival is higher or lower than the expected patient survival. "Statistically Higher" survival corresponds to better outcomes, while "Statistically Lower" survival corresponds to worse outcomes. If the p-value is greater than 0.05 then this line reads "Not Significantly Different". This value is not shown if the expected patient survival is not calculated.

Percent Retransplanted

This line reports the percentage the total number of transplants that are retransplanted during the given timeframe -- one month, one year or three years. A patient is considered to have been retransplanted if the patient receives a subsequent transplant of the same organ in that timeframe.

Follow-up Days Reported

This line reports the percentage of days that are targeted for inclusion during the follow-up period relative to the number of days that were actually reported with OPTN transplant recipient follow-up forms. Days which were covered only by data from the SSDMF or CMS death data are not included in this percentage even though these days are included in the analyses.

For patients who did not die before the end of the period, the targeted number of days of follow-up is the entire period (30, 365, or 1096 days; see next section for details on maximum follow-up). For grafts transplanted during the last 6 months of the period, the targeted follow-up for 1 year survival is 6 months. For patients who died before the end of the period, the number of targeted days of follow-up is the number of days until death. The total number of days of follow-up reported for all patients are summed and divided by the total number of days of follow-up targeted to obtain the percent reported in this line. This percentage is a measure of how dependent the results are on outside sources of data. A low percent of follow-up days reported indicates that there may be under-ascertainment of mortality for the facility since the completeness of follow-up data is still partially determined by center reporting.

Maximum Days of Follow-up

Patients were followed for up to 30 days for the 1-month statistics, up to 365 days for the 1-year statistics and up to 1096 days for the 3-year statistics starting at the day of transplant (day 1). The maximum follow-up time for patients in the center is reported on this line. If this maximum is less than 30 days for the 1-month, 365 for the 1-year or 1096 for the 3-year statistics, then the patient survival reported is not a reliable estimate of the true patient survival for the time period.

Review Criteria (preview site only)
This section contains information used by the OPTN Membership and Professional Standards Committee (MPSC) to flag centers for review: (1) Observed/Expected greater than 1.5, (2) Observed minus Expected greater than 3, (3) one-sided P-value less than 0.05; an additional row indicates whether the center has been flagged for each survival cohort. This section is for each center’s information and review and will not appear on the public version of the reports.

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XII. Technical Notes on Computing Expected Patient or Graft Survival

Model Fitting Methods

Survival models are adjusted for patient characteristics. The model used for each organ is adjusted for patient characteristics specific to that organ, so we refer to the list of characteristics generically with the notation x. Individual patients are numbered sequentially and we refer generically to the i^th patient. The specific values of the characteristics for patient i are denoted by x_i. Based on a model, we calculate S_i(t), the probability of survival to time t for patients with characteristics x_i. The probability of survival at time point t0 for patient i is S_i(t₀). The average survival for the n accrued transplant patients at the center is calculated as (1/n) ΣS_i(t₀) (Zucker). The expected number of events during follow-up for each patient was calculated as -ln(S_i(t_i)) where S_i(t_i) is the survival curve adjusted to the characteristics of patient i, and t_i is the follow-up time for that patient up to time t₀ (SAS/STAT User's Guide, Andersen, Collett). The expected number of events is Σ-ln(S_i(t_i )) for the n transplants during the follow-up times for the patients at this center.

The Risk-Adjustment tables indicate the value of the coefficient for each characteristic in each of the models (beta) as well as the corresponding standard error and a p-value indicating if the coefficient is significantly different than 0. The relative risk (RR) for mortality or graft loss associated with a particular patient characteristic, compared to the reference group for that characteristic, can be calculated as RR=exp(beta). For continuous variables, this is interpreted as the RR associated with 1 unit higher value (e.g. for ischemia time, it would be the RR associated with 1 hour longer time). However, keep in mind that these models are estimated for the purposes of adjustment, not for interpretation of coefficients. Some standard errors are large, which reflects uncertainty in the interpretation of the corresponding covariate, but does not adversely affect the accuracy of the adjusted estimate. For example, coefficients more negative than -7 can occur when there are no events in the corresponding group of patients.

Missing Data

In general, patients with missing values for variables entered into the model as categorical variables were included in their own category or in the reference group. Missing values for variables entered into the model as continuous values were either replaced with the mean value (these mean values are included as footnotes in the Risk-Adjustment tables) or with a value of 0. In some cases there is also a categorical variable indicating whether the value was missing. Note that characteristics such as age are included in some models as categorical variables and in others as continuous variables.

The Risk-Adjustment tables list all the covariates included in each model and indicates (indirectly) how missing values were handled in each particular case. Looking at the variables corresponding to a particular characteristic or value in a model will indicate whether missing values are included in a category. If there is no category that includes the missing values, patients with missing values are included with the reference group. For continuous values, there may be a category for those with missing values, but patients with missing values are also assigned a value for the continuous variable itself. If the reference indicated for the variable is the average value then missing values are replaced with this average value (listed in the footnotes for each Risk-Adjustment model). In these cases where the reference is the average value, the average value is subtracted from the patient’s actual value as described below in the calculation section. Replacing missing values with this average therefore ultimately results in a 0 value for patients with missing data. If the reference is not indicated or is 0, then missing values are replaced with 0. In these case, the actual value is used, again resultsing a 0 value for patients with missing data. Using the average value or a value of 0 for missing data does not affect the resulting estimates of coefficients, but it is necessary to know what was done when carrying out calculations based on these tables. The interpretation of the percent of patients with a functioning graft or alive at a particular time point is affected by this choice since this percent survival is calculated when all covariates are equal to 0.

Notes on Diagnosis, Ischemia Time, and Other Continuous Variables

Adjusting for Diagnosis

In models adjusting for diagnosis, the diagnosis groups and reference groups differ by organ and in some cases by age group.

Kidney - 6 groups for adult models:

glomerular diseases (reference group)
diabetes
hypertensive nephrosclerosis
polycystic kidney disease
renovascular and other vascular diseases
other/missing (includes tubular and interstitial diseases, and congenital, familial, and
    metabolic kidney diseases)

Kidney - 4 groups for pediatric models:

tubular and interstitial diseases, and congenital, familial, and metabolic kidney
    diseases (reference) focal segmental glomerulosclerosis (FSG)
other glomerular diseases
other/missing (includes diabetes, hypertensive nephrosclerosis, and renovascular
    and other vascular diseases)

Liver - 6 groups for adult models, 7 for pediatric models:

cholestatic liver disease/cirrhosis
non-cholestatic cirrhosis (reference for adult models)
acute hepatic necrosis (AHN)
metabolic disease
malignancy
other/missing
For pediatric models only: biliary atresia (reference for pediatric models)

Ischemia Time and Other Continuous Variables

Ischemia time refers to cold ischemia time for kidney and liver transplants, total time for heart transplants and maximum time for lung transplants. In all models, ischemia time was measured in hours. Ischemia time was included in the models as a linear term with an indicator for missing ischemia time. In some models there is also a quadratic term. In all but the kidney models, ischemia time was centered on the average ischemia time (i.e. the average value was subtracted from the patient’s actual value) by organ and missing values were set to the mean as described in the previous section. In the (deceased donor) kidney models, missing values for ischemia time were set to 0 and there is an indicator for missing ischemia time as in the other models. The mean values are included as footnotes in the corresponding Risk-Adjustment tables.

Other instances in which continuous variables are included in the models are treated similarly. In cases where the reference value indicated for a continuous variable is the average value, the continuous term is centered on the mean and missing values are set equal to the mean as described in the previous section. Again, the mean values are included as footnotes in the corresponding Risk-Adjustment tables.

Calculation of Individual Expected Survival

The tables of coefficients can be used to calculate the expected graft or patient survival at 1 month, 1 year, and 3 years for a specific patient. The 1-year model is used for both the 1 month and 1 year calculations and the 3-year model is used for the 3-year calculation. In addition to the coefficients in the models, the tables show the corresponding baseline survival values. The 1-year models show the percent of patients with a functioning graft or percent alive at 1 month and at 1 year. The 3-year models show the percent of patients with a functioning graft or percent alive at 3 years.

Suppose that p is the number of patient characteristics listed in the appropriate model table and x_ij is the specific value of the j^th characteristic for the i^th patient. For patient i, we calculate:

X_i'ß = ß₁x_i1 + ß₂x_i2+ ... + ß_px_ip

where ß_j is the j^th coefficient from the model.

For a categorical characteristic, the value is 1 if the patient falls into the category and 0 otherwise. For continuous characteristics, subtract the average value (or 3.5 for HLA mismatch) given in the Risk-Adjustment Models from the patient's value for that characteristics before multiplying by the corresponding ß_i. Missing values are set to the mean value before this subtraction and thus result in a 0 for the patient. For example, for linear ischemia time, subtract the average ischemia time from the patient's ischemia time (in hours) before multiplying by the corresponding ß_i. For quadratic ischemia time, subtract the average ischemia time from the patient's ischemia time (in hours) and square it before multiplying by the corresponding ß_i. For continuous characteristic for which the table indicates that the reference is 0 or for which no reference is indicated, the patient’s value is used directly with no subtraction. Missing values for such variables are set to 0, again resulting in a 0 for the patient.

The Cox model yields estimates of the coefficients b_j and the baseline survival curve, S₀(t). For patient i, with characteristics:

x_i = x_i1, x_i2, ... , x_ip

we calculate

S_i(t₀) = [S₀(t₀)]^exp(x_i'ß) ,

the expected survival at time point t₀ (t₀ = 1 month, 1 year, or 3 years).

Then

S_Avg(t₀) = (1/N) S_i(t₀)

is the expected survival at time t₀ for this facility. For the “All” donor tables for kidney and liver transplant recipients, the values for living and deceased donor recipients are averaged.

We also calculate

S_i(t_i) = [S₀(t_i)]^exp(x_i'ß)

Then -ln(S_i(t_i )) is equal to the expected number of events for patient i during follow-up and

-ln[S_i(t_i)]

is the expected number of events during follow-up at the facility shown in Tables 10 and 11. Note that although these expected numbers of events have been calculated for all patients and summarized in Tables 10 and 11 as just described, the information shown on the model coefficients table is generally not sufficient for a user to calculate the expected number of events for a patients. This is because for patients who died or were censored before the end of the period, the end of follow-up (t_i) will not be equal to the time points for which the baseline survival is reported on the model coefficients table (i.e., not equal to 1 month, 1 year or 3 years). The model coefficient tables are intended instead for use in calculating average expected survival at specific time points (1 month, 1 year, and 3 years).

NOTATION:

N = number of transplants accrued
t₀ = reporting time point (e.g. 1 month, 1 year, 3 years)
t_i = end of follow-up for patient i during period. Note t_i < t₀ for patients who die or are lost to follow-up during the period.
S₀(t₀) = fraction surviving to time t₀ (e.g., 1 month, 1 year, 3 years) when all covariates are equal to 0. This is the Nelson-Aalen (empirical) cumulative hazard function estimate and appears at the top of the corresponding table of coefficients.
S_i(t₀) = fraction surviving to time t₀ (e.g., 1 month, 1 year, 3 years) adjusted to characteristics of patient i
S_Avg(t₀) = expected fraction surviving to time t₀ (e.g., 1 month, 1 year, 3 years) adjusted to average characteristics of patients at the facility

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References

1. Andersen PK, Borgun O, Gill RD, Keiding N. Statistical Models Based on Counting Processes. Springer-Verlag, New York. 1993. See pages 334 and 406-407.
   
2. Breslow NE, Day NE. Statistical methods in cancer research (Volume II), IARC, Lyon, 1987.
   
3. Colett D, Modeling Survival Data in Medical Research. Chapman and Hall, London, 1994. See page 153 equation 5.6 and page 151, equation 5.1. Cox DR. Regression Models and life tables (with discussion). J R Stat Soc 1972; 34: 197-220.
   
4. Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J. Am. Stat. Assoc. 1972; 53:457-481.
   
5. SAS Institute Inc., Ref SAS/STAT User’s Guide, Version 8, Cary, North Carolina: SAS Institute Incorporated, 1999, p 2598-99.
   
6. Zucker DM. Restricted mean life with covariates: modification and extension of a useful survival analysis method. J. Amer. Statist. Assoc. 1998; 93:702-709.