Organ Nonutilization Following Revision to the Public Health Service Donor Risk Criteria for HIV, HCV, or HBV Transmission.

BACKGROUND: Organs from Public Health Service criteria (PHSC) donors, previously referred to as PHS infectious-risk donors, have historically been recovered but not used, traditionally referred to as "discard," at higher rates despite negligible risk to recipients. On March 1, 2021, the definition of PHSC donors narrowed to include only the subset of donors deemed to have meaningfully elevated risk in the current era of improved infectious disease testing. METHODS: Using Scientific Registry of Transplant Recipients data from May 1, 2019, to December 31, 2022, we compared rates of PHSC classification and nonutilization of PHSC organs before versus after the March 1, 2021, policy change among recovered decedents using the χ2 tests. We performed an adjusted interrupted time series analysis to examine kidney and liver recovery/nonuse (traditionally termed "discard") and kidney, liver, lung, and heart nonutilization (nonrecovery or recovery/nonuse) prepolicy versus postpolicy. RESULTS: PHSC classification dropped sharply from 24.5% prepolicy to 15.4% postpolicy (P < 0.001). Before the policy change, PHSC kidney recovery/nonuse, liver nonuse, lung nonuse, and heart nonuse were comparable to non-PHSC estimates (adjusted odds ratio: kidney = 0.981.061.14, P = 0.14; liver = 0.850.921.01, P = 0.07; lung = 0.910.991.08, P = 0.83; heart = 0.890.971.05, P = 0.47); following the policy change, PHSC kidney recovery/nonuse, liver nonuse, lung nonuse, and heart nonuse were lower than non-PHSC estimates (adjusted odds ratio: kidney = 0.770.840.91, P < 0.001; liver = 0.770.840.92, P < 0.001; lung = 0.740.810.90, P < 0.001; heart = 0.610.670.73, P < 0.001). CONCLUSIONS: Even though PHSC donors under the new definition are a narrower and theoretically riskier subpopulation than under the previous classification, PHSC status appears to be associated with a reduced risk of kidney and liver recovery/nonuse and nonutilization of all organs. Although historically PHSC organs have been underused, our findings demonstrate a notable shift toward increased PHSC organ utilization.

Racial Disparities in Waiting List Outcomes of Patients Listed for Lung Transplantation.

BACKGROUND: The Lung Allocation Score, implemented in 2005, prioritized lung transplant candidates by medical urgency rather than waiting list time and was expected to improve racial disparities in transplant allocation. We evaluated whether racial disparities in lung transplant persisted after 2005. METHODS: We identified all wait-listed adult lung transplant candidates in the United States from 2005 through 2021 using the Scientific Registry of Transplant Recipients. We evaluated the association between race and receipt of a transplant by using a multivariable competing risk regression model adjusted for demographics, socioeconomic status, Lung Allocation Score, clinical measures, and time. We evaluated interactions between race and age, sex, socioeconomic status, and Lung Allocation Score. RESULTS: We identified 33,158 candidates on the lung transplant waiting list between 2005 and 2021: 27,074 White (82%), 3350 African American (10%), and 2734 Hispanic (8%). White candidates were older, had higher education levels, and had lower Lung Allocation Scores (P < .001). After multivariable adjustment, African American and Hispanic candidates were less likely to receive lung transplants than White candidates (African American: adjusted subhazard ratio, 0.86; 95% CI, 0.82-0.91; Hispanic: adjusted subhazard ratio, 0.82; 95% CI, 0.78-0.87). Lung transplant was significantly less common among Hispanic candidates aged >65 years (P = .003) and non-White candidates from higher-poverty communities (African-American: P = .013; Hispanic: P =.0036). CONCLUSIONS: Despite implementation of the Lung Allocation Score, racial disparities persisted for wait-listed African American and Hispanic lung transplant candidates and differed by age and poverty status. Targeted interventions are needed to ensure equitable access to this life-saving intervention.

A2/A2B to B deceased donor kidney transplantation in the Kidney Allocation System era.

Kidney transplantation from blood type A2/A2B donors to type B recipients (A2→B) has increased dramatically under the current Kidney Allocation System (KAS). Among living donor transplant recipients, A2-incompatible transplants are associated with an increased risk of all-cause and death-censored graft failure. In light of this, we used data from the Scientific Registry of Transplant Recipients from December 2014 until June 2022 to evaluate the association between A2→B listing and time to deceased donor kidney transplantation (DDKT) and post-DDKT outcomes for A2→B recipients. Among 53 409 type B waitlist registrants, only 12.6% were listed as eligible to accept A2→B offers ("A2-eligible"). The rates of DDKT at 1-, 3-, and 5-years were 32.1%, 61.4%, and 72.1% among A2-eligible candidates and 14.1%, 29.9%, and 44.1% among A2-ineligible candidates, with the former experiencing a 133% higher rate of DDKT (Cox weighted hazard ratio (wHR) = 2.192.332.47; P < .001). The 7-year adjusted mortality was comparable between A2→B and B-ABOc (type B/O donors to B recipients) recipients (wHR 0.780.941.13, P = .5). Moreover, there was no difference between A2→B vs B-ABOc DDKT recipients with regards to death-censored graft failure (wHR 0.771.001.29, P > .9) or all-cause graft loss (wHR 0.820.961.12, P = .6). Following its broader adoption since the implementation of the kidney allocation system, A2→B DDKT appears to be a safe and effective transplant modality for eligible candidates. As such, A2→B listing for eligible type B candidates should be expanded.

Renal Function at Discharge Among Kidney Recipients Experiencing Delayed Graft Function and Its Associations With Long-term Outcomes.

Delayed graft function (DGF) after kidney transplantation is associated with higher rates of acute rejection and poor graft survival and outcomes. Current DGF definitions based on posttransplant need for dialysis are not standardized and there are no objective methodologies for quantifying DGF severity. Methods: Using Organ Procurement and Transplantation Network data, we examined DGF, and used recipient serum creatinine at discharge as a correlate of renal function and DGF severity (mild: <2.5 mg/dL; severe: ≥2.5 mg/dL). The associations between donor and recipient factors and DGF severity were quantified using logistic regression. We also examined the associations between DGF severity and long-term recipient outcomes, adjusting for potential confounders. Results: A predictive model using donor and recipient factors had a reasonably good ability to discriminate mild (low creatinine) versus severe (high creatinine) DGF (c-statistic of 0.70). In Cox regression, DGF and creatinine at discharge were both independently associated with long-term outcomes, yet their effects differed depending on the outcome (graft function, death-censored graft function, recipient mortality). Our findings suggest that having DGF, but with relatively good renal function (creatinine <2.5) at discharge, may be less deleterious on graft and recipient survival compared with severe, prolonged DGF, which was associated with a decreased median graft survival of ~2.6 y compared with no DGF with low creatinine at discharge. Conclusions: Our novel DGF severity stratification identified unique factors associated with DGF severity, along with DGF's association with long-term graft and patient survival. The adverse cost and outcome implications of severe DGF warrant additional investigation to improve kidney transplantation practice.

The Independent Effects of Procurement Biopsy Findings on 10-Year Outcomes of Extended Criteria Donor Kidney Transplants.

Introduction: The role of procurement biopsies in deceased donor kidney evaluation is debated in light of uncertainty about the influence of biopsy findings on recipient outcomes. The literature is filled with conflicting and ambiguous findings typically derived from small studies focused on short-term outcomes or reliant on biopsies prepared by methods impractical in the time-sensitive context of organ procurement. Methods: After manual data entry of DonorNet attachments from 4480 extended criteria donors (ECDs) recovered in the United States from 2008 to 2012, we applied causal inference methods in a Cox regression framework to estimate independent effects of glomerulosclerosis (GS), interstitial fibrosis, and vascular changes on long-term kidney graft survival. Kidney discard rates from 2018 to 2019 were evaluated to characterize contemporary kidney utilization patterns. Results: Effects of interstitial fibrosis and vascular changes were largely attenuated after adjusting for potentially confounding donor and recipient variables, although conclusions are less certain for severe levels due to smaller sample sizes. By contrast, significant effects of GS (>10% vs. 0%-5%) persisted even after adjustment (all-cause, hazard ratio [HR] 1.18; 95% CI 1.06, 1.28; death-censored, HR 1.28; 95% CI 1.08, 1.46) but plateaued beyond 10%. By contrast, kidney discard rates increased precipitously as GS rose >10%. Conclusion: Despite being obtained under less than ideal conditions, estimated GS from a procurement biopsy is independently associated with long-term graft survival, above and beyond standard clinical parameters, in ECD transplants. However, the disproportionately high likelihood of discard for kidneys with GS >10% is unjustified. The outsized effect of GS on kidney utilization should be tempered and commensurate with its effect on outcomes.

Ethics-by-design: efficient, fair and inclusive resource allocation using machine learning.

The distribution of crucial medical goods and services in conditions of scarcity is among the most important, albeit contested, areas of public policy development. Policymakers must strike a balance between multiple efficiency and fairness objectives, while reconciling disparate value judgments from a diverse set of stakeholders. We present a general framework for combining ethical theory, data modeling, and stakeholder input in this process and illustrate through a case study on designing organ transplant allocation policies. We develop a novel analytical tool, based on machine learning and optimization, designed to facilitate efficient and wide-ranging exploration of policy outcomes across multiple objectives. Such a tool enables all stakeholders, regardless of their technical expertise, to more effectively engage in the policymaking process by developing evidence-based value judgments based on relevant tradeoffs.

Developing simultaneous liver-kidney transplant medical eligibility criteria while providing a safety net: A 2-year review of the OPTN's allocation policy.

The OPTN's simultaneous liver-kidney (SLK) allocation policy, implemented August 10, 2017, established medical eligibility criteria for adult SLK candidates and created Safety Net kidney allocation priority for liver-alone recipients with new/continued renal impairment. OPTN SLK and kidney after liver (KAL) data were analyzed (registrations as of December 31, 2019, transplants pre-policy [March 20, 2015-August 9, 2017] vs. post-policy [August 10, 2017-December 31, 2019]). Ninety-four percent of SLK registrations met eligibility criteria (99% CKD: 50% dialysis, 50% eGFR). SLK transplant volume decreased from a record 740 (2017) to 676 (2018, -9%), with a subsequent increase to 728 (2019, 1.6% below 2017 volume). For KAL listings within 1 year of liver transplant, waitlist mortality rates declined post-policy versus pre-policy (27 [95% CI = 20.6-34.7] vs. 16 [11.7-20.5]) while transplant rates increased fourfold (46 [32.2-60.0] vs. 197 [171.6-224.7]). There were 234 KAL transplants post-policy (94% Safety Net priority eligible), and no significant difference in 1-year patient/graft survival vs. kidney-alone (patient: 95.9% KAL, 97.0% kidney-alone [p = .39]; graft: 94.2% KAL, 94.6% kidney-alone [p = .81]). From pre- to post-policy, the proportion of all deceased donor kidney and liver transplants that were SLK decreased (kidney: 5.1% to 4.3%; liver: 9.7% to 8.7%). SLK policy implementation interrupted the longstanding rise in SLK transplants, while Safety Net priority directed kidneys to liver recipients in need with thus far minimal impact to posttransplant outcomes.

The Advantage of Multiple Listing Continues in the Kidney Allocation System Era.

BACKGROUND: Transplant candidates can be listed at multiple transplant centers to increase the probability of receiving an organ. We evaluated the association between multilisting (ML) status and access to a deceased donor kidney transplant (DDKT) to determine if ML provides a long-term advantage regarding wait-list mortality and recipient outcomes. MATERIALS AND METHODS: Candidates between January 2010 and October 2017 were identified as either singly or multiply listed using Organ Procurement and Transplantation Network data and cohorts before and after implementation of the Kidney Allocation System (KAS). Cross-sectional logistic regression was used to assess relationships between candidate factors and ML prevalence (5.4%). RESULTS: Factors associated with ML pre-KAS included having blood type B (reference, type O; odds ratio [OR], 1.20; P < .001), having private insurance (OR, 1.5; P < .001), wait time (OR, 1.28; P < .001), and increasing calculated panel-reactive antibody (cPRA) (reference, cPRA 0-100; OR for cPRA 80-98, 2.83; OR for cPRA 99, 3.47; OR for cPRA 100, 5.18; P < .001). Transplant rates were double for multilisted vs singly listed recipients (adjusted hazard ratio [aHR], 2.16; P < .001). Extra-donor service area ML candidates received transplants 2.5 years quicker than single-listing (SL) candidates, conferring a 42% wait-list advantage. Recipient death (aHR, 0.94; P = .122) and graft failure (aHR, 0.91; P = .006) rates were also lower for ML recipients. CONCLUSIONS: In the KAS era, ML continues to increase the likelihood of receiving a DDKT and lower the incidence of wait-list mortality, and it confers a survival advantages over SL.

A revealed preference analysis to develop composite scores approximating lung allocation policy in the U.S.

BACKGROUND: The patient ranking process for donor lung allocation in the United States is carried out by a classification-based, computerized algorithm, known as the match system. Experts have suggested that a continuous, points-based allocation framework would better serve waiting list candidates by removing hard boundaries and increasing transparency into the relative importance of factors used to prioritize candidates. We applied discrete choice modeling to match run data to determine the feasibility of approximating current lung allocation policy by one or more composite scores. Our study aimed to demystify the points-based approach to organ allocation policy; quantify the relative importance of factors used in current policy; and provide a viable policy option that adapts the current, classification-based system to the continuous allocation framework. METHODS: Rank ordered logistic regression models were estimated using 6466 match runs for 5913 adult donors and 534 match runs for 488 pediatric donors from 2018. Four primary attributes are used to rank candidates and were included in the models: (1) medical priority, (2) candidate age, (3) candidate's transplant center proximity to the donor hospital, and (4) blood type compatibility with the donor. RESULTS: Two composite scores were developed, one for adult and one for pediatric donor allocation. Candidate rankings based on the composite scores were highly correlated with current policy rankings (Kendall's Tau ~ 0.80, Spearman correlation > 90%), indicating both scores strongly reflect current policy. In both models, candidates are ranked higher if they have higher medical priority, are registered at a transplant center closer to the donor hospital, or have an identical blood type to the donor. Proximity was the most important attribute. Under a points-based scoring system, candidates in further away zones are sometimes ranked higher than more proximal candidates compared to current policy. CONCLUSIONS: Revealed preference analysis of lung allocation match runs produced composite scores that capture the essence of current policy while removing rigid boundaries of the current classification-based system. A carefully crafted, continuous version of lung allocation policy has the potential to make better use of the limited supply of donor lungs in a manner consistent with the priorities of the transplant community.

Risk of ESRD in prior living kidney donors.

We studied End-Stage Renal Disease (ESRD) in living kidney donors (LKDs) who donated in the United States between 1994 and 2016 (n = 123 526), using Organ Procurement and Transplantation Network and Centers for Medicare and Medicaid Services data. Two hundred eighteen LKDs developed ESRD, with a median of 11.1 years between donation and ESRD. Absolute 20-year risk was low but not uniform, with risk associated with race, age, and sex and increasing exponentially over time. LKDs had increased risk of ESRD if they were male (adjusted hazard ratio [aHR]: 1.75, 95% confidence interval [95%CI]: 1.33-2.31), had higher BMI (aHR: 1.34 per 5 kg/m2 , 95%CI: 1.10-1.64) or lower estimated GFR (aHR: 0.89 per 10 mL/min, 95% CI: 0.80-0.99), were first-degree relatives of the recipient (parent: [aHR: 2.01, 95% CI: 1.26-3.21]; full sibling [aHR: 1.87, 95%CI: 1.23-2.84]; identical twin [aHR: 19.79, 95%CI: 7.65-51.24]), or lived in lower socioeconomic status neighborhoods at donation (aHR: 0.87 per $10k increase; 95%CI: 0.77-0.99). We found a significant interaction between donation age and race, with higher risk at older ages for white LKDs (aHR: 1.26 per decade, 95%CI: 1.04-1.54), but higher risk at younger ages for black LKDs (aHR: 0.75 per decade, 95%CI: 0.57-0.99). These findings further inform risk assessment of potential LKDs.

Early Experience with the New Kidney Allocation System: A Perspective from UNOS.

PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2017_11_21_CJASNPodcast_18_1_v.mp3.

Diagnosing the Decades-Long Rise in the Deceased Donor Kidney Discard Rate in the United States.

BACKGROUND: The proportion of deceased donor kidneys recovered for transplant but discarded increased steadily in the United States over 2 decades, from 5.1% in 1988 to 19.2% by 2009. Over 100 000 patients are waiting for a kidney transplant, yet 3159 kidneys were discarded in 2015. METHODS: We evaluated trends in donor characteristics, discard reasons, and Organ Procurement Organization-specific discard rates. Multivariable regression and propensity analysis were used to estimate the proportion of the discard rate rise in the 2000s attributable to changes in donor factors and decisions to biopsy and pump kidneys. RESULTS: This study found that at least 80% of the discard rate rise can be explained by the recovery of kidneys from an expanding donor pool and changes in biopsy and pumping practices. However, a residual discard rate increase could not be explained by changes in these factors. From 1987 to 2009, median donor age rose from 26 to 43 years; median Kidney Donor Risk Index increased from 1.1 in 1994 to 1.3 in 2009. Our findings suggest that the increase from 10% to 30% in the proportion of kidneys pumped during the 2000s served as a buffer, keeping the discard rate from rising even higher than it did. CONCLUSIONS: The majority of the kidney discard rate rise can be explained by the broadening donor pool. However, the presence of an unexplained, residual increase suggests behavioral factors (eg, increased risk aversion) and/or allocation inefficiencies may have played a role. Reducing risk aversion, improving allocation, and more often pumping less-than-ideal, yet potentially transplantable kidneys, may help reverse the trend.

Delays in Prior Living Kidney Donors Receiving Priority on the Transplant Waiting List.

BACKGROUND AND OBJECTIVES: Prior living donors (PLDs) receive very high priority on the Organ Procurement and Transplantation Network (OPTN) kidney waiting list. Program delays in adding PLDs to the waiting list, setting their status to active, and submitting requests for PLD priority can affect timely access to transplantation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We used the OPTN and the Centers for Medicare and Medicaid Services data to examine timing of (1) listing relative to start of dialysis, (2) activation on the waiting list, and (3) requests for PLD priority relative to listing date. There were 210 PLDs (221 registrations) added to the OPTN kidney waiting list between January 1, 2010 and July 31, 2015. RESULTS: As of September 4, 2015, 167 of the 210 PLDs received deceased donor transplants, six received living donor transplants, two died, five were too sick to transplant, and 29 were still waiting. Median waiting time to deceased donor transplant for PLDs was 98 days. Only 40.7% of 221 PLD registrations (n=90) were listed before they began dialysis; 68.3% were in inactive status for <90 days, 17.6% were in inactive status for 90-365 days, 8.6% were in inactive status for 1-2 years, and 5.4% were in inactive status for >2 years. Median time of PLDs waiting in active status before receiving PLD priority was 2 days (range =0-1450); 67.4% of PLDs received PLD priority within 7 days after activation, but 15.4% waited 8-30 days, 8.1% waited 1-3 months, 4.1% waited 3-12 months, and 5.0% waited >1 year in active status for PLD priority. After receiving priority, most were transplanted quickly. Median time in active status with PLD priority before deceased donor transplant was 23 days. CONCLUSIONS: Fewer than one half of listed PLDs were listed before starting dialysis. Most listed PLDs are immediately set to active status and receive PLD priority quickly, but a substantial number spends time in active status without PLD priority or a large amount of time in inactive status, which affects access to timely transplants.

The role of procurement biopsies in acceptance decisions for kidneys retrieved for transplant.

BACKGROUND AND OBJECTIVES: There is a shortage of kidneys for transplant, and many patients on the deceased donor kidney transplant waiting list would likely benefit from kidneys that are currently being discarded. In the United States, the most common reason given for discarding kidneys retrieved for transplant is procurement biopsy results. This study aimed to compare biopsy results from discarded kidneys with discard attributed to biopsy findings, with biopsy results from comparable kidneys that were successfully transplanted. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In this retrospective, observational, case-control study, biopsy reports were examined from 83 kidneys discarded in 2010 due to biopsy findings (cases), 83 contralateral transplanted kidneys from the same donor (contralateral controls), and 83 deceased donors randomly matched to cases by donor risk profile (randomly matched controls). A second procurement biopsy was obtained in 64 of 332 kidneys (19.3%). RESULTS: The quality of biopsy reports was low, with amounts of tubular atrophy, interstitial inflammation, arteriolar hyalinosis, and acute tubular necrosis often not indicated; 69% were wedge biopsies and 94% used frozen tissue. The correlation between first and second procurement biopsies was poor; only 25% of the variability (R(2)) in glomerulosclerosis was explained by biopsies being from the same kidney. The percentages of glomerulosclerosis overlapped substantially between cases, contralateral controls, and randomly matched controls: 17.1%±15.3%, 9.0%±6.6%, and 5.0%±5.9%, respectively. Of all biopsy findings, only glomerulosclerosis>20% was independently correlated with discard (cases versus contralateral controls; odds ratio, 15.09; 95% confidence interval, 2.47 to 92.41; P=0.003), suggesting that only this biopsy result was used in acceptance decisions. One-year graft survival was 79.5% and 90.7% in contralateral and randomly matched controls, respectively, versus 91.6% among all deceased donor transplants in the Scientific Registry of Transplant Recipients. CONCLUSIONS: Routine use of biopsies could lead to unnecessary kidney discards.