OPTN/SRTR 2021 Annual Data Report: Introduction

David P. Schladt¹, Ajay K. Israni^1,2,3

¹Scientific Registry of Transplant Recipients, Hennepin Healthcare Research Institute, Minneapolis, MN

²Department of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN

³Department of Medicine, Hennepin Healthcare, University of Minnesota, Minneapolis, MN

Abstract

The OPTN/SRTR 2021 Annual Data Report presents the status of the solid organ transplantation system in the United States from 2010 through 2021. Organ-specific chapters are presented for kidney, pancreas, liver, intestine, heart, and lung transplant. Each organ-specific chapter is organized to present waitlist information, donor information (both deceased and living, as appropriate), transplant information, and patient outcomes. Data pertaining to pediatric patients are generally presented separately from the adult data. In addition to the organ-specific chapters, you will find chapters dedicated to deceased organ donation, vascularized composite allograft, and the COVID-19 pandemic. The data presented in the Annual Data Report are descriptive in nature. In other words, most tables and figures present raw data without statistical adjustment for possible confounding or changes over time. Therefore, the reader should keep in mind the observational nature of the data when attempting to draw inferences before trying to ascribe a cause to any observed patterns or trends. This introduction provides a brief overview of trends in waitlist and transplant activity. More detailed descriptions can be found in the respective organ-specific chapters.

Keywords: allocation, transplant, waiting list

1 TRENDS IN KIDNEY TRANSPLANT

In 2021, 141,807 adult and pediatric candidates were on the kidney waiting list at some point (Figure INT 1), an increase of 0.3% from 2020. Notably, however, the size of the kidney waiting list in 2021 was similar to the size in 2020, both down from a high of 146,639 in 2019. The number of new candidates added to the kidney waiting list in 2021 increased to 42,852. This is an 11.4% increase from 38,482 in 2020 (Figure INT 3). The number of kidney transplants also increased in 2021 to 25,487, a 7.8% increase from 2020 (Figure INT 5). Despite these advances, the proportion of kidneys from deceased donors recovered for the purpose of transplant but ultimately not transplanted increased to about 25%, 15.5% higher than in 2020 (Figure INT 7). Among transplant recipients from 2014 through 2016, 1-year patient survival was 97.2% and 5-year patient survival was 88.2% (Figure INT 8).

2 TRENDS IN PANCREAS TRANSPLANT

The demand for pancreas transplant has continued to decline, likely due to improvements in the medical treatment of diabetes. Since 2010, the number of candidates on the waiting list for pancreas-alone or pancreas-after-kidney transplant has generally declined, from 1,950 in 2010 to 1,026 in 2021. The only increase occurred in 2021 after a low of 999 in 2020, likely due to the COVID-19 pandemic (Figure INT 2). The number of candidates waiting for a combined kidney-pancreas transplant declined from 3,794 in 2010 to 3,211 in 2021, with declines in all but 2 years: 2019 and 2021. Trends were similar in the number of new additions to the pancreas transplant waiting list, with declines to 317 for pancreas-alone and pancreas-after-kidney in 2021 and 1,488 for simultaneous kidney-pancreas (Figure INT 4). The total number of pancreas transplants performed in the United States was 963 in 2021, almost the same as the 962 in 2020; this represents a 5.1% decline from 2019 (Figure INT 6). Patient survival after pancreas transplant is similar to that after kidney transplant and higher than that for all other organs. In the cohort of recipients from 2014 through 2016, 1-year patient survival was 95.8% and 5-year patient survival was 88.8% (Figure INT 8).

3 TRENDS IN LIVER TRANSPLANT

The number of adult and pediatric candidates on the liver waiting list has remained fairly consistent since 2010, ranging from a high of 28,622 in 2011 to a low of 26,004 in 2021 (Figure INT 1). The year 2021 marked the fifth consecutive year of declines in the liver waiting list. Although the total number of candidates on the liver waiting list has been slowly declining in recent years, the number of additions to it has been generally increasing since 2014 (Figure INT 3). In 2021, 13,831 candidates were added to the waiting list, a 6.2% increase over the previous year. The number of transplants increased to 9,234 in 2021, a 3.7% increase from 2020 (Figure INT 5). The proportion of livers recovered for transplant but not transplanted was 10.0% in 2021 (Figure INT 7). Recipient survival from 2014 through 2016 was 91.7% at 1 year and 81.7% at 5 years (Figure INT 8).

4 TRENDS IN INTESTINE TRANSPLANT

In 2021, 364 candidates were on the waiting list for an intestine transplant for at least 1 day (Figure INT 2) and 143 new candidates were added to the intestine waiting list (Figure INT 4). The number of intestine transplants remained small, with 96 performed in 2021 (Figure INT 6). This represents a 36% decline in yearly intestine transplants since 2010. Among intestine transplant recipients from 2014 through 2016, 1-year survival was 81.0% and 5-year survival was 59.7% (Figure INT 8).

5 TRENDS IN HEART TRANSPLANT

The first full year of the new heart allocation system, which incorporates six medical urgency statuses rather than the previous three-tier system, was 2019. In 2021, there were 8,665 candidates on the heart waiting list for at least 1 day, which is similar to the count in 2019 (8,650 candidates) (Figure INT 2). Of these patients, 5,076 were newly added to the list in 2021 (Figure INT 2). The number of heart transplants performed in 2021 reached a record high of 3,862, a 4.0% increase over 2020 (Figure INT 6). Among the cohort of recipients from 2014 through 2016, 1-year patient survival was 91.1% and 5-year survival was 81.0% (Figure INT 8).

6 TRENDS IN LUNG TRANSPLANT

The year 2021 saw 2,569 lung transplants performed (Figure INT 6) among 4,186 patients who were on the waiting list at some point (Figure INT 2). New listings in 2021 accounted for 3,158 of the 4,186 candidates on the list (Figure INT 4). The 2,569 lung transplants performed in 2021 was a 6.8% decrease from the record high of 2,759 in 2019. Among recipients from 2014 through 2016, 1-year survival was 87.8% and 5-year survival was 60.5% (Figure INT 8).

7 SUMMARY

The year 2021 set another record for the number of solid organ transplants performed in the United States. Since 2010, the number of kidney transplants has increased by 44%; liver transplants, by 47%; heart transplants, by 63%; and lung transplants, by 42%. During the same period, there was a decline for pancreas and intestine transplants of 18% and 36%, respectively. The number of newly listed candidates increased in 2021 compared with 2020 for kidney, pancreas, liver, lung, and heart transplants. This is a sign of recovery from the COVID-19 pandemic. The waitlist additions outpace the number of transplants performed for all organs, which exemplifies the supply-demand imbalance in solid organ transplantation. Each organ-specific chapter of this Annual Data Report presents a more detailed look at the status of organ donation and transplantation in the United States.

This publication was produced for the U.S. Department of Health and Human Services (HHS), Health Resources and Services Administration (HRSA), by Hennepin Healthcare Research Institute (HHRI) and the United Network for Organ Sharing (UNOS) under contracts HHSH75R60220C00011 and HHSH250201900001C, respectively.

This publication lists nonfederal resources in order to provide additional information to consumers. The views and content in these resources have not been formally approved by HHS or HRSA. Neither HHS nor HRSA endorses the products or services of the listed resources.

The OPTN/SRTR 2021 Annual Data Report is not copyrighted. Readers are free to duplicate and use all or part of the information contained in this publication. Data are not copyrighted and may be used without permission if appropriate citation information is provided.

Pursuant to 42 U.S.C. 1320b-10, this publication may not be reproduced, reprinted, or redistributed for a fee without specific written authorization from HHS.

Suggested Citations:
Full citation: Organ Procurement and Transplantation Network (OPTN) and Scientific Registry of Transplant Recipients (SRTR). OPTN/SRTR 2021 Annual Data Report. U.S. Department of Health and Human Services, Health Resources and Services Administration; 2023. Accessed [insert date]. http://srtr.transplant.hrsa.gov/annual_reports/Default.aspx
Abbreviated citation: OPTN/SRTR 2021 Annual Data Report. HHS/HRSA; 2023. Accessed [insert date]. http://srtr.transplant.hrsa.gov/annual_reports/Default.aspx

Publications based on data in this report or supplied on request must include a citation and the following statement: The data and analyses reported in the OPTN/SRTR 2021 Annual Data Report have been supplied by the United Network for Organ Sharing and Hennepin Healthcare Research Institute under contract with HHS/HRSA. The authors alone are responsible for reporting and interpreting these data; the views expressed herein are those of the authors and not necessarily those of the U.S. government.

This report is available at https://srtr.transplant.hrsa.gov. Individual chapters may be downloaded.

List of Figures

Figure INT 1: All candidates on the kidney or liver waiting list
Figure INT 2: All candidates on the waiting list for organs other than isolated kidney or liver
Figure INT 3: New candidates added to the kidney or liver waiting list during the year
Figure INT 4: New candidates added to the waiting list during the year for organs other than isolated kidney or liver
Figure INT 5: Total counts of kidney or liver transplants
Figure INT 6: Total counts of transplants for organs other than isolated kidney or liver
Figure INT 7: Rates of organs recovered for transplant and not transplanted
Figure INT 8: Patient survival among all transplant recipients, 2014-2016, by organ

**All candidates on the kidney or liver waiting list.** Candidates listed at multiple centers are counted once per listing. Includes active and inactive candidates on the list any time during the year.

Figure INT 1: All candidates on the kidney or liver waiting list. Candidates listed at multiple centers are counted once per listing. Includes active and inactive candidates on the list any time during the year.

**All candidates on the waiting list for organs other than isolated kidney or liver.** Candidates listed at multiple centers are counted once per listing. Includes active and inactive candidates on the list any time during the year. PAK, pancreas after kidney; PTA, pancreas transplant alone.

Figure INT 2: All candidates on the waiting list for organs other than isolated kidney or liver. Candidates listed at multiple centers are counted once per listing. Includes active and inactive candidates on the list any time during the year. PAK, pancreas after kidney; PTA, pancreas transplant alone.

**New candidates added to the kidney or liver waiting list during the year.** A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Active and inactive patients are included.

Figure INT 3: New candidates added to the kidney or liver waiting list during the year. A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Active and inactive patients are included.

**New candidates added to the waiting list during the year for organs other than isolated kidney or liver.** A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Active and inactive patients are included.

Figure INT 4: New candidates added to the waiting list during the year for organs other than isolated kidney or liver. A new candidate is one who first joined the list during the given year, without having been listed in a previous year. Previously listed candidates who underwent transplant and subsequently relisted are considered new. Active and inactive patients are included.

**Total counts of kidney or liver transplants.** Kidney: patients undergoing kidney or SPK transplant. Retransplants and multiorgan transplants are included. SPK, simultaneous pancreas-kidney.

Figure INT 5: Total counts of kidney or liver transplants. Kidney: patients undergoing kidney or SPK transplant. Retransplants and multiorgan transplants are included. SPK, simultaneous pancreas-kidney.

**Total counts of transplants for organs other than isolated kidney or liver.** Pancreas: patients undergoing pancreas or SPK transplant. Heart: patients undergoing heart or heart-lung transplant. Lung: patients undergoing lung or heart-lung transplant. Retransplants and multiorgan transplants are included. SPK, simultaneous pancreas-kidney.

Figure INT 6: Total counts of transplants for organs other than isolated kidney or liver. Pancreas: patients undergoing pancreas or SPK transplant. Heart: patients undergoing heart or heart-lung transplant. Lung: patients undergoing lung or heart-lung transplant. Retransplants and multiorgan transplants are included. SPK, simultaneous pancreas-kidney.

**Rates of organs recovered for transplant and not transplanted.** Percentage of organs not transplanted out of all organs recovered for transplant. Kidneys and lungs recovered en bloc are counted once, and those recovered separately are counted twice.

Figure INT 7: Rates of organs recovered for transplant and not transplanted. Percentage of organs not transplanted out of all organs recovered for transplant. Kidneys and lungs recovered en bloc are counted once, and those recovered separately are counted twice.

**Patient survival among all transplant recipients, 2014-2016, by organ.** Patient survival estimated using unadjusted Kaplan-Meier methods. Similar overall survival rates for kidney and pancreas recipients may obscure one organ's line on the graph.

Figure INT 8: Patient survival among all transplant recipients, 2014-2016, by organ. Patient survival estimated using unadjusted Kaplan-Meier methods. Similar overall survival rates for kidney and pancreas recipients may obscure one organ’s line on the graph.