1 INTRODUCTION

This chapter reports data collected by the Organ Procurement and Transplantation Network (OPTN) to describe changes in deceased donor characteristics over the past decade and deceased organ donor metrics such as donation rate, organ yield, and rate of organs recovered for transplant but not transplanted (ie, nonuse). These metrics are currently produced by the Scientific Registry of Transplant Recipients (SRTR), and some, such as organ yield, are used for organ procurement organization (OPO) quality assessment by OPTN. Some data described in this chapter are also used by the Centers for Medicare & Medicaid Services (CMS) to develop its own quality assessment of OPOs. The chapter also describes the Centers for Disease Control and Prevention’s (CDC’s) national data on deaths that will be used by CMS as part of its metrics to assess OPO quality. In 2019, the federal government ordered the revision of OPO quality metrics “to establish more transparent, reliable, and enforceable objective metrics for evaluating an OPO’s performance.”¹ This federal order also aims to reduce organ nonuse nationally. CMS has approved new metrics to assess OPO quality.² The impact of new metrics to assess OPO quality will be seen after they are implemented in 2022.

2 DONORS

There were 41,346 transplants in the United States from organs recovered in 2021, a 5.9% increase from 39,028 in 2020; this number has been increasing since 2012. The number of deceased donor transplants increased to 34,807, a 4.5% increase from 33,303 in 2020; this number has also been increasing since 2012. There were 13,862 deceased donors in 2021, a 10.1% increase from 12,588 in 2020, and an increase from 11,870 deceased donors in 2019, 10,721 in 2018, and 10,286 in 2017; this number has been increasing since 2010. The increase may be explained in part by the rising number of deaths of young people due to the ongoing opioid epidemic. In 2021, 6,539 living donor transplants (ie, difference between overall transplants and deceased donor transplants) were performed, an increase from 5,725 in 2020 and a decrease from 7,391 in 2019 and 6,843 in 2018; this number increased from 2016 to 2019. Thus, living donor transplants are recovering from the negative impact of the COVID-19 pandemic. In 2021, 13,102 individuals met the definition of eligible death according to OPTN policy, a slight increase from 12,696 in 2020. In 2021, 22,359 imminent neurologic and eligible deaths were reported, a slight increase from 21,446 in 2020, 20,934 in 2019, 21,259 in 2018, and 22,258 in 2017, and a decline from 23,441 in 2016. The decline was anticipated due to changes in the OPTN definition of imminent neurologic and eligible deaths (Figure DD 1) (eg, changing the absence of three brainstem reflexes to the absence of spontaneous breathing and two other brainstem reflexes).

Donations after brain death (DBDs) increased to 9,673 in 2021, a 3.2% increase from 9,364 in 2020, and from 9,152 in 2019, 8,589 in 2018, and 8,403 in 2017; this number has been increasing since 2012. Donations after circulatory death (DCDs) increased to 4,189 in 2021, a 29.9% increase from 3,224 in 2020, and from 2,718 in 2019, 2,132 in 2018, and 1,883 in 2017; this number has been increasing since 2009 (Figure DD 2). Potential reasons for the increases in DBD and DCD donors include rising numbers of deaths of young people due to the opioid epidemic, new innovations in perfusion methods, and increasing use of organs from DBD donors.

Consistent with the increasing number of DBD and DCD donations, 99,714 organs were authorized in 2021, a 10.4% increase from 90,310 organs in 2020; this number has been increasing since 2010. In 2021, 49,100 organs were recovered, a 10.5% increase from 44,426 in 2020 and an increase from 43,717 in 2019; this number has been increasing since 2012. In 2021, 35,700 organs were transplanted, an increase of 4.3% from 34,220 in 2020 and an increase from 33,302 in 2019; this number has been increasing since 2012 (Figure DD 3).

3 DONATION RATE

Any metric based solely on eligible deaths uses only a subset of potential donors, because successful donations can come from donors not meeting the eligible death definition (eg, DCD or donors older than 75 years). Recognizing this limitation, SRTR’s current donation rate measures how often a person with an eligible death becomes a donor. Unadjusted donation rates varied by donation service area (DSA), ranging from 54.1 to 88.4 eligible donors per 100 eligible deaths (Figure DD 4). Risk-adjusted donation rates are presented for each OPO semiannually in OPO reports on the SRTR website.

The overall donation rate was 70.1 eligible donors per 100 eligible deaths in 2021. As expected, donation rates varied by organ (Figure DD 5). In 2021, the highest rate was for kidney, followed by liver, heart, lung, and pancreas. The kidney donation rate was 66.2 eligible donors per 100 eligible deaths in 2021. The next highest donation rate after kidney in 2021 was liver, at 60.3 donors per 100 eligible deaths (Figure DD 5). The donation rates for heart, lung, and pancreas were 27.6, 17.9, and 9.4 donors per 100 eligible deaths, respectively.

4 ORGANS RECOVERED PER DONOR

In 2021, 3.33 organs were recovered per donor, slightly lower than the 3.41 in 2020, 3.51 in 2019, 3.53 in 2018, and 3.54 in 2017 (Figure DD 6). Given that each donor can potentially donate two kidneys, the ORPD was highest for kidney, at 1.90 in 2021, a slight increase from 1.89 in 2020 and from 1.87 in 2019 (Figure DD 6). The ORPD for liver was 0.69, a slight decrease from 0.73 in 2020 and 0.77 in 2019 (Figure DD 7). Over the past decade, ORPDs have remained stable for kidney and slightly decreased for liver. The ORPD for heart was 0.28 in 2021, a slight decrease from 0.29 in 2020 and 0.30 in 2019. The ORPD for lung was 0.37 in 2021, a slight decrease from 0.39 in 2020 and 0.44 in 2019. These declines in ORPD may have been due to the COVID-19 pandemic; whether they will reverse in subsequent years remains to be seen (Figure DD 7). The ORPD for pancreas was 0.09 in 2021, the same as in 2020 and a decrease from 0.11 in 2019, but this decline has been ongoing for the past decade. In 2020, the ORPD varied substantially by DSA, ranging from 2.56 to 3.66 (Figure DD 8). The ORPD is an unadjusted number representing a mix of donor types, including young, old, DBDs, and DCDs, which explains some differences observed.

5 ORGANS TRANSPLANTED PER DONOR

The number of OTPDs was 2.75 in 2021, a decrease from 2.90 in 2020, 3.01 in 2019, 3.06 in 2018, and 3.07 in 2017 (Figure DD 9). Given that each donor can potentially donate two kidneys, the OTPD was highest for kidney, followed by liver (Figures DD 9 and 10). The OTPD for kidney was 1.43 in 2021, a decrease from 1.48 in 2020, and 1.50 in 2019 (Figure DD 10). In 2021, the OTPD for other individual organs was 0.62 for liver, 0.34 for lung, 0.28 for heart, 0.07 for pancreas, and 0.007 for intestine. The OTPD for all organs varied by DSAs and ranged from 1.87 to 3.27 (Figure DD 11).

The OTPD varies depending on whether the donation was DBD or DCD. Accounting for all organs, the OTPD was 3.18 for DBD donors and 1.75 for DCD donors (Figure DD 12). For kidney, the OTPD was 1.45 and 1.38 for DBD and DCD donors, respectively. This was the first year in a decade that the OTPD for kidney was lower for DCD compared with DBD (Figure DD 13). The difference was wider for all other organs, with a higher OTPD for DBD than DCD donors (Figures DD 14, 15, 16, 17, and 18). No intestines were transplanted from DCD donors. A few hearts were transplanted from DCD donors starting in 2019.

Numbers of deceased donor organs transplanted in 2021 were 19,762 kidneys (9,702 left kidneys, 9,509 right kidneys, and 551 en bloc kidneys), 964 pancreata, 8,595 livers, 96 intestines, 3,861 hearts, and 2,443 lungs (Figures DD 23, 24, 25, 26, 27, 28, 29, and 30). Numbers of deceased donor organs transplanted in 2020 included 18,410 kidneys (9,113 left kidneys, 9,021 right kidneys, and 276 en bloc kidneys), 962 pancreata, 8,350 livers, 91 intestines, 3,722 hearts, and 2,463 lungs. Therefore, in 2021, the number of deceased donor organs transplanted increased for all organs except for lung. The number of deceased donor lungs transplanted in 2020 may have decreased because of the COVID-19 pandemic and then increased in 2021 as the transplant community adjusted to the pandemic. In a 2021 unadjusted analysis, not accounting for the mix of DBD and DCD donor types, OTPD varied substantially by DSA, ranging from 1.87 to 3.27, a range similar to the 1.92 to 3.41 in 2020 (Figure DD 11).

The OTPD from DBD donors was 3.17 in 2021, down from 3.25 in 2020, 3.33 in 2019, and 3.34 in 2018. The OTPD from DCD donors was 1.74 in 2021, down from 1.89 in 2020 and from 1.94 in 2019 and 2018 (Figure DD 12).

In 2021, among kidney donors, OTPD varied by kidney donor profile index (KDPI), at 1.91, 1.82, 1.45, and 0.54 for KDPI <20%, 21%-34%, 35%-85%, and >85%, respectively (Figure DD 19). The trends seem relatively stable over the past decade (Figure DD 19).

6 ORGANS RECOVERED FOR TRANSPLANT BUT NOT TRANSPLANTED

The number of nonused organs is calculated by subtracting the number of organs transplanted from the number of organs recovered for transplant. The nonuse rate is then calculated by dividing nonused organs by the number of organs recovered for transplant. The nonuse rate in 2021 for all organs combined was 17.6 per recovered organ, higher than the 15.0 per recovered organ in 2020, 14.3 per recovered organ in 2019, and 13.2 per recovered organ in 2018 and 2017 (Figure DD 20). This trend in increasing annual nonuse has persisted since 2017. In 2021, the percentages for kidney, pancreas, liver, intestine, heart, and lung were 24.6, 26.2, 9.90, 1.03, 1.00, and 8.1 per recovered organ, respectively, and slightly increased from 21.3, 23.2, 9.3, 5.4 per recovered donor for kidney, pancreas, liver, and lung in 2020. In contrast, the percentages were higher in 2020 for intestine, at 3.2 per recovered donor. The percentages for heart were similar in 2021 and 2020. The number for kidney nonuse increased the most in 2021 (Figures DD 23, 24, 25, 26, 27, 28, 29, and 30). In 2021, 2,951 left kidneys, 3,149 right kidneys, 184 en bloc kidneys, 343 pancreata, 945 livers, 1 intestine, 39 hearts, and 188 lungs were recovered for transplant but not transplanted. In 2020, 2,290 left kidneys, 2,399 right kidneys, 181 en bloc kidneys, 294 pancreata, 861 livers, 3 intestines, 39 hearts, and 115 lungs were recovered for transplant but not transplanted. Thus, the absolute nonuse number for all organs increased from 2020 to 2021, except for intestine and heart.

7 USE OF DCD ORGANS AND HIGH-KDPI KIDNEYS ACROSS OPOs

Use of DCD organs varied across OPOs, from 0% to 53% of all deceased donors, in 2021 (Figure DD 21). In 2021, the percentage of DCD donor organs among deceased donor transplant recipients varied across DSAs, from 0% to 44.4%, a narrower range than in 2020. In 2021, the percentage of kidney donors with KDPI higher than 85% also varied across DSAs, from 1.14 to 17.5, a wider range than 0.70 to 15.18 in 2020 and 0 to 16.8 in 2019 (Figure DD 22).

8 DISPOSITION OF ORGANS

The disposition of each organ from actual donors is described in Figures DD 23, 24, 25, 26, 27, 28, 29, and 30. For left, right, and en bloc kidneys, the most common reason for recovered for transplant but not transplanted was “no recipient located, list exhausted,” followed by “biopsy findings.” For pancreata, the most common reasons were “other” and “anatomical abnormalities.” For livers, the most common reason was by “other, specify” followed by “biopsy findings.” The reasons for the one intestine nonused was “recipient determined to be unsuitable for transplantation in the operating room.” For hearts, the most common reason was “other, specify.” For lungs, the most common reason was “other, specify” and “poor organ function.” These reasons are similar to those in 2020. Donor characteristics from 2021 are compared with those in 2011 in Table DD 1. The most remarkable difference was the increase in HIV-positive donors to 30 in 2021, from none in 2011. This increase is due to the 2013 HIV Organ Policy Equity (HOPE) Act, which modified rules about organ donation between HIV-positive individuals and authorized use of these organs as part of clinical research. Other remarkable differences were an increase in anoxia as cause of donor death, from 28% in 2011 to 47.3% in 2021, and decreases in stroke (36.1% to 25%) and head trauma (33% to 24.1%). The percentage of DCD donors increased from 13% in 2011 to 30.2% in 2021. The increase in numbers of donors from 2011 to 2021 (8,126 to 13,862) and those with anoxia as cause of death may be due to the opioid epidemic.

New CMS metrics were finalized and published in December 2021 for the OPO public performance report. This new metric is being used in 2022. The new metrics determine the CMS potential donors, which is the denominator for both the donation rate and transplant rate metrics. In Table DD 2, the CMS potential donors were identified using data obtained from the CDC’s National Center for Health Statistics Detailed Multiple Cause of Death (MCOD) file. The International Classification of Diseases, Tenth Revision, codes used to identify potential donor deaths include 120-125 for ischemic heart disease, 160-169 for cerebrovascular disease, and V-1-Y89 for external causes of morbidity and mortality, which includes blunt trauma, gunshot wound, drug overdose, suicide, drowning, and asphyxiation. Thus, the definition of potential donors is based on the cause of death, age younger than 75 years, and the location of death being consistent with organ donation, mainly inpatient deaths. The number of donors is the numerator for the donation rate and is defined as the number of deceased individuals from whom at least one organ, such as heart, liver, lung, kidney, pancreas, or intestine, was transplanted. The number of donors also includes donors with pancreata or islet cells that were either recovered for research or recovered for transplant but submitted for research. Figure DD 31 and Table DD 2 show that the donation rate metric varied across OPOs from 5.82 to 19.14 in 2020.

The second CMS metric, for transplant rate, uses number of organs transplanted from deceased donors as shown in Table DD 2. This numerator also includes pancreata and islet cells that are either recovered for research or recovered for transplant but submitted for research. The CMS transplant rate varied across OPOs from 18.7 to 60.0 in 2020 (Figure DD 32). The CMS transplant rate was lowest for the Hawaii OPO, and the metric for this OPO only includes transplanted kidneys in its numerator.