(Stewart et al. 2017). The increased discards resulting from changes in the donor pool and the increased biopsy rate were partially offset by an increase in the percentage of kidneys that were machine perfused – i.e. “pumped” – between 1999 and 2009 (8.7 to 30 percent) to keep the kidneys healthier and allow more logistical flexibility in scheduling surgery. Taken all together, changes in these factors over time explain most, but not all, of the increase in the discard rate between 1999 and 2009 (Stewart et al. 2017). Though the utility of “Biopsy Findings” is debated, it is the most commonly reported reason for discard (38.2 percent), the fact that there is significant geographic variation in the odds of discard across the United States suggests that factors other than organ quality contribute to kidney discard (Mohan et al. 2018). 12 The percentage of discards reported as “no recipient located—list exhausted (indicating the OPO attempted but was unable to find a transplant center willing to accept the kidney)” rose from 10 to nearly 30 percent between 2008 and 2015 (Stewart et al. 2017). This suggests allocative inefficiency, but it also may indicate increased risk aversion by transplant centers. CMS established Medicare conditions for participation of transplant centers for the first time in 2007 (CMS 2007). Programs would be graded based on transplant graft and recipient survival rates, and programs with lower than expected survival rates would be judged out of compliance. This metric could discourage the acceptance and utilization of kidneys that are transplantable but less than perfect. While survival outcomes are risk adjusted, many feel that the process does not adequately reflect all risks, leading many centers to become risk averse and limit access to transplantation (Woodside and Sung 2016). Some low performing programs have responded by reducing their transplant volume (Schold et al. 2013) and becoming more selective in deciding which kidneys to accept (Schold et al. 2010). In 2016, eighteen percent of kidneys recovered from deceased donors were discarded (USRDS 2018). Administration Policies to Increase the Supply of Kidneys for Transplantation In 2020, HHS issued regulations13 that will hold OPOs accountable to objective performance standards. In particular, HHS focused on two new outcome measures—the donation rate and the organ transplant rate. Both would compare performance between OPOs as measured respectively by numbers of donors and organs transplanted to a more objective, CDC reported measure in the denominator–i.e., as a percentage of inpatient deaths in the donation service area, 75 years or younger with any cause of death that is not a contraindication organ donation. Moreover, these changes would hold OPOs accountable by requiring them to meet specified performance targets for these measures. OPOs that failed to do so could face possible decertification and replacement by higher-performing OPOs. HHS estimates that their changes to the OPO system alone could generate up to 4,500 additional kidney transplants per year by 2026. However, HHS notes that there is uncertainty regarding the number of kidney transplants their rules will engender. 12 Kidney quality though is an important factor - the median KDRI of discarded kidneys was 1.78 compared with 1.12 for transplanted kidneys. Mohan supra. 13 Organ Procurement Organizations Conditions for Coverage: Revisions to the Outcome Measure Requirements for Organ Procurement Organizations, 85 FR 77898 CEA • Increasing the Number of Kidney Transplants to Treat End Stage Renal Disease 14 How Many Additional Deceased Donor Kidneys Could be Obtained? An important first step to estimate the number of additional deceased donor kidneys that could be obtained is considering the number of potential donors, which provides an upper bound on how many additional kidneys could be obtained. Starting with the total number of deaths each year, the number of potential donors decreases at each step of the organ recovery process (see figure 3) due to various exclusion criteria, including age and medical comorbidities, so that ultimately only a fraction of decedents can become deceased organ donors. Based on these criteria, the OPTN Deceased Donor Potential Study (Klassen et al. 2016) estimated that there were roughly 38,000 potential donors in 2010. When compared to the actual donors that year they estimated a “realization rate” (actual/estimated potential donors) of 19.2 percent overall (Klassen et al. 2016). The shortfall was particularly severe in the 50-64 (14.8 percent realization rate) and 65-75 (4.0 percent realization rate) donor age groups (Klassen et al. 2016). A more recent study estimated the “donation percentage” (actual/possible deceased donors) to be 31.1 percent across all age groups (Goldberg et al. 2017). Building on these studies, the Bridgespan (2019) study estimated 17,000 additional kidneys could be obtained from deceased donors in the United States by more accurately identifying and utilizing potential deceased donors. However, this number is optimistic, as it assumes 100 percent consent to donate rates and 100 percent utilization of recovered organs (Bridgespan 2019), both of which are unrealistic because those rates are likely unachievable. As previously noted, 18 percent of donated kidneys