Geographic disparities in donor lung supply and lung transplant waitlist outcomes: A cohort study

Despite the Final Rule mandate for equitable organ allocation in the United States, geographic disparities exist in donor lung allocation, with the majority of donor lungs being allocated locally to lower‐priority candidates. We conducted a retrospective cohort study of 19 622 lung transplant candidates waitlisted between 2006 and 2015. We used multivariable adjusted competing risk survival models to examine the relationship between local lung availability and waitlist outcomes. The primary outcome was a composite of death and removal from the waitlist for clinical deterioration. Waitlist candidates in the lowest quartile of local lung availability had an 84% increased risk of death or removal compared with candidates in the highest (subdistribution hazard ratio [SHR]: 1.84, 95% confidence interval [CI]: 1.51‐2.24, P < .001). The transplantation rate was 57% lower in the lowest quartile compared with the highest (SHR: 0.43, 95% CI: 0.39‐0.47). The adjusted death or removal rate decreased by 11% with a 50% increase in local lung availability (SHR: 0.89, 95% CI: 0.85‐0.93, P < .001) and the adjusted transplantation rate increased by 19% (SHR: 1.19, 95% CI: 1.17‐1.22, P < .001). There are geographically disparate waitlist outcomes in the current lung allocation system. Candidates listed in areas of low local lung availability have worse waitlist outcomes.     

Balancing supply and demand: Review of the 2018 donor heart allocation policy

Heart transplant remains the most effective treatment for patients with end stage heart failure. Advances in mechanical circulatory support devices have changed the therapeutic landscape and contributed to a demographic shift in patients awaiting transplant. In the setting of a growing waitlist and concern for an inability of current policies to accurately account for patient acuity and equitable geographic distribution of organs, the United Network for Organ Sharing developed a new donor heart allocation policy which was introduced in 2018. The new policy creates more precise listing criteria to reflect patient acuity, addresses previously marginalized groups, and takes steps to address geographic inequalities.     

Survival and renal function after liver transplantation alone in patients meeting the new United Network for Organ Sharing simultaneous liver-kidney criteria

In 2017, United Network for Organ Sharing (UNOS) implemented a simultaneous liver-kidney transplant (SLK) allocation policy. Our institution uses a more restrictive criteria for SLK; thus, we have a group of patients that would have qualified for SLK under the new allocation policy but received liver transplantation alone (LTA). We compared survival and post-operative renal function in patients that received LTA stratified by whether they met the new UNOS SLK criteria. There was no difference in graft and patient survival. The majority (95%) of LTA patients meeting the UNOS SLK criteria did not need dialysis at 1 year, with a mean eGFR increase from 23 mL/min preoperatively to 48 mL/min at 1 year. Of those with eGFR ≤ 20 mL/min at 1 month after surgery, the majority did regain adequate renal function. The implementation of the UNOS SLK allocation policy was appropriate in the previously unregulated area. This policy provides an excellent framework for those that may benefit from SLK. Our data suggest that a more restrictive policy may be possible in order to promote the best use of donated organs. The current safety net is appropriately positioned to capture patients in need of subsequent kidney transplant.     

A Share 21 model in liver transplantation: Impact on waitlist outcomes

With the introduction of Model for End‐Stage Liver Disease‐Sodium (MELD‐Na)–based allocation, the score at which patients benefit from liver transplantation (LT) has shifted from a score of 15 to 21. This study aimed to evaluate waitlist outcomes in patients with MELD‐Na scores <21 and explore the utility of replacing “Share 15” with “Share 21.” The study uses data from the Organ Procurement and Transplantation Network/United Network for Organ Sharing registry. All adult patients registered for LT after implementation of the MELD‐Na–based allocation were evaluated. Waitlist patients with initial and final scores <21 were eligible. Patients with exception scores were excluded. To explore the potential impact of a Share 21 model, patients with an initial MELD‐Na score of 6‐14 (Group 1) and those with a score of 15‐20 (Group 2) were compared for waitlist outcomes. There were 3686 patients with an initial score of 6‐14 (Group 1) and 3282 with a score of 15‐20 (Group 2). Group 2, when compared to Group 1, showed comparable risk of mortality (adjusted hazard ratio [aHR] 1.00, P = .97), higher transplant probability (aHR 3.25, P < .001), and lower likelihood of removal from listing because of improvement (aHR 0.74, P = .011). Share 21 may enhance transplant opportunities and increase parity for patients with higher MELD‐Na scores without compromising waitlist outcomes.     

Attitudes toward organ donation among waitlisted transplant patients: results of a cross‐sectional survey

Organ shortage remains a major barrier to transplantation. While many efforts have focused on educating the general population regarding donation, few studies have examined knowledge regarding donation and donor registration rates among waitlisted candidates. We aimed to determine waitlisted patients' willingness to donate, elucidate attitudes surrounding organ allocation, and identify barriers to donation. A cross‐sectional survey was distributed to assess demographics, knowledge regarding organ donation, and attitudes regarding the allocation process. Responses from 225 of 579 (39%) waitlisted patients were collected. Seventy‐one respondents (32%) were registered donors, while 64 patients (28%) noted no interest in participating in donation. A total of 19% of respondents felt their medical treatment would change by being a donor, while 86 patients (38%) felt their condition precluded them from donation. Forty patients (18%) felt they should be prioritized on the waitlist if they agreed to donate. A minority of patients (28%) reported discussion of organ donation with their physician. Waitlisted candidates constitute a population of willing, although often unregistered, organ donors. Moreover, many endorse misconceptions regarding the allocation process and their donation eligibility. In a population for which transplantation is not always possible, education is needed regarding organ donation among waitlisted patients, as this may enhance donation rates.     

Predictors of low risk for dropout from the liver transplant waiting list for hepatocellular carcinoma in long wait time regions: Implications for organ allocation

All patients with hepatocellular carcinoma meeting United Network for Organ Sharing T2 criteria currently receive the same listing priority for liver transplant (LT). A previous study from our center identified a subgroup with a very low risk of waitlist dropout who may not derive immediate LT benefit. To evaluate this issue at a national level, we analyzed within the United Network for Organ Sharing database 2052 patients with T2 hepatocellular carcinoma receiving priority listing from 2011 to 2014 in long wait time regions 1, 5, and 9. Probabilities of waitlist dropout were 18.3% at 1 year and 27% at 2 years. In multivariate analysis, factors associated with a lower risk of waitlist dropout included Model for End‐Stage Liver Disease‐Na < 15, Child's class A, single 2‐ to 3‐cm lesion, and α‐fetoprotein ≤20 ng/mL. The subgroup of 245 (11.9%) patients meeting these 4 criteria at LT listing had a 1‐year probability of dropout of 5.5% vs 20% for all others (P < .001). On explant, the low dropout risk group was more likely to have complete tumor necrosis (35.5% vs 24.9%, P = .01) and less likely to exceed Milan criteria (9.9% vs 17.7%, P = .03). We identified a subgroup with a low risk of waitlist dropout who should not receive the same LT listing priority.     

Simultaneous Liver–Kidney Allocation Policy: A Proposal to Optimize Appropriate Utilization of Scarce Resources

The introduction of the Mayo End‐Stage Liver Disease score into the Organ Procurement and Transplantation Network (OPTN) deceased donor liver allocation policy in 2002 has led to a significant increase in the number of simultaneous liver–kidney transplants in the United States. Despite multiple attempts, clinical science has not been able to reliably predict which liver candidates with renal insufficiency will recover renal function or need a concurrent kidney transplant. The problem facing the transplant community is that currently there are almost no medical criteria for candidacy for simultaneous liver–kidney allocation in the United States, and this lack of standardized rules and medical eligibility criteria for kidney allocation with a liver is counter to OPTN's Final Rule. Moreover, almost 50% of simultaneous liver–kidney organs come from a donor with a kidney donor profile index of ≤0.35. The kidneys from these donors could otherwise be allocated to pediatric recipients, young adults or prior organ donors. This paper presents the new OPTN and United Network of Organ Sharing simultaneous liver–kidney allocation policy, provides the supporting evidence and explains the rationale on which the policy was based.     

Does Lung Donation by Heart Donors Have an Impact on Survival in Heart Transplant Recipients?

Lung procurement is increasing during multiorgan recovery and substantially alters the explant process. This study evaluated whether lung donation by a heart donor affects survival in heart transplant recipients. Retrospective analysis of United Network for Organ Sharing (UNOS) adult heart transplantation data from 1998 to 2012 was performed. Lung donors (LDs) were defined as those having at least one lung procured and transplanted. Non‐LDs had neither lung transplanted. Heart transplant recipients who had previous transplants, who had heterotopic transplants, who were waitlisted for other organs or who were temporarily delisted were excluded from the analysis. Kaplan–Meier survival analysis and Cox proportional hazards regression were performed. Of 23 590 heart transplant recipients meeting criteria during the study period, 8638 (36.6%) transplants were from LDs. Donors in the LD group had less history of cigarette use (15.5% vs. 29.5%, p < 0.001). On univariate analysis, LDs were associated with improved patient survival (p < 0.001). On multivariate analysis, LDs were not significantly associated with patient survival (adjusted hazard ratio 0.98, 95% confidence interval 0.94–1.03). Analysis of the UNOS registry suggested that donor pulmonary status and lung procurement had no detrimental effect on survival in heart transplant recipients, supporting the present practice of using donor lungs whenever possible.     

Utilization of Deceased Donor Kidneys to Initiate Living Donor Chains

We propose that some deceased donor (DD) kidneys be allocated to initiate nonsimultaneous extended altruistic donor chains of living donor (LD) kidney transplants to address, in part, the huge disparity between patients on the DD kidney waitlist and available donors. The use of DD kidneys for this purpose would benefit waitlisted candidates in that most patients enrolled in kidney paired donation (KPD) systems are also waitlisted for a DD kidney transplant, and receiving a kidney through the mechanism of KPD will decrease pressure on the DD pool. In addition, a LD kidney usually provides survival potential equal or superior to that of DD kidneys. If KPD chains that are initiated by a DD can end in a donation of an LD kidney to a candidate on the DD waitlist, the quality of the kidney allocated to a waitlisted patient is likely to be improved. We hypothesize that a pilot program would show a positive impact on patients of all ethnicities and blood types.     

Use of Population‐based Data to Demonstrate How Waitlist‐based Metrics Overestimate Geographic Disparities in Access to Liver Transplant Care

Liver allocation policies are evaluated by how they impact waitlisted patients, without considering broader outcomes for all patients with end‐stage liver disease (ESLD) not on the waitlist. We conducted a retrospective cohort study using two nationally representative databases: HealthCore (2006–2014) and five‐state Medicaid (California, Florida, New York, Ohio and Pennsylvania; 2002–2009). United Network for Organ Sharing (UNOS) linkages enabled ascertainment of waitlist‐ and transplant‐related outcomes. We included patients aged 18–75 with ESLD (decompensated cirrhosis or hepatocellular carcinoma) using validated International Classification of Diseases, Ninth Revision (ICD‐9)–based algorithms. Among 16 824 ESLD HealthCore patients, 3‐year incidences of waitlisting and transplantation were 15.8% (95% confidence interval [CI] : 15.0–16.6%) and 8.1% (7.5–8.8%), respectively. Among 67 706 ESLD Medicaid patients, 3‐year incidences of waitlisting and transplantation were 10.0% (9.7–10.4%) and 6.7% (6.5–7.0%), respectively. In HealthCore, the absolute ranges in states' waitlist mortality and transplant rates were larger than corresponding ranges among all ESLD patients (waitlist mortality: 13.6–38.5%, ESLD 3‐year mortality: 48.9–62.0%; waitlist transplant rates: 36.3–72.7%, ESLD transplant rates: 4.8–13.4%). States' waitlist mortality and ESLD population mortality were not positively correlated: ρ = ?0.06, p‐value = 0.83 (HealthCore); ρ = ?0.87, p‐value = 0.05 (Medicaid). Waitlist and ESLD transplant rates were weakly positively correlated in Medicaid (ρ = 0.36, p‐value = 0.55) but were positively correlated in HealthCore (ρ = 0.73, p‐value = 0.001). Compared to population‐based metrics, waitlist‐based metrics overestimate geographic disparities in access to liver transplantation.     

Equal Opportunity Supplemented by Fair Innings: Equity and Efficiency in Allocating Deceased Donor Kidneys

For 7 years, the Kidney Transplantation Committee of the United Network for Organ Sharing/Organ Procurement Transplantation Network has attempted to revise the kidney allocation algorithm for adults (≥18 years) in end‐stage renal disease awaiting deceased donor kidney transplants. Changes to the kidney allocation system must conform to the 1984 National Organ Transplant Act (NOTA) which clearly states that allocation must take into account both efficiency (graft and person survival) and equity (fair distribution). In this article, we evaluate three allocation models: the current system, age‐matching and a two‐step model that we call “Equal Opportunity Supplemented by Fair Innings (EOFI)”. We discuss the different conceptions of efficiency and equity employed by each model and evaluate whether EOFI could actually achieve the NOTA criteria of balancing equity and efficiency given current conditions of growing scarcity and donor‐candidate age mismatch.     

The survival advantage of pancreas after kidney transplant

Patient survival after pancreas after kidney transplant ( PAK) has been reported to be inferior to patient survival after simultaneous pancreas–kidney transplant (SPK). The authors examine national data to further explore allograft (kidney and pancreas) and patient survival after PAK. Kaplan–Meier and Cox proportional hazard models were used to analyze Organ Procurement and Transplantation Network data from 1995 to 2010. The analysis compared PAK and SPK candidates and recipients. Kaplan–Meier analysis results showed that PAK after either a living or a deceased donor kidney transplant is associated with increased kidney graft survival compared with recipients with type 1 diabetes who received only a kidney. The best kidney allograft survival was for patients who received a living donor kidney followed by PAK. Receiving a living donor kidney was associated with increased pancreas allograft survival compared with receiving a deceased donor kidney. PAK transplant recipients who receive both organs have a survival advantage compared with uremic candidates who receive neither (SPK waitlist). Compared with uremic diabetic waitlist patients, SPK and PAK recipients showed similar overall patient survival. Successful PAK offers a survival advantage compared with receiving neither a kidney nor a pancreas transplant. These data also suggest that receiving a pancreas (after kidney) transplant may have a protective effect on the kidney allograft.     

Measuring and monitoring equity in access to deceased donor kidney transplantation

The Organ Procurement and Transplantation Network monitors progress toward strategic goals such as increasing the number of transplants and improving waitlisted patient, living donor, and transplant recipient outcomes. However, a methodology for assessing system performance in providing equity in access to transplants was lacking. We present a novel approach for quantifying the degree of disparity in access to deceased donor kidney transplants among waitlisted patients and determine which factors are most associated with disparities. A Poisson rate regression model was built for each of 29 quarterly, period‐prevalent cohorts (January 1, 2010‐March 31, 2017; 5 years pre–kidney allocation system [KAS], 2 years post‐KAS) of active kidney waiting list registrations. Inequity was quantified as the outlier‐robust standard deviation (SD_w) of predicted transplant rates (log scale) among registrations, after “discounting” for intentional, policy‐induced disparities (eg, pediatric priority) by holding such factors constant. The overall SD_w declined by 40% after KAS implementation, suggesting substantially increased equity. Risk‐adjusted, factor‐specific disparities were measured with the SD_w after holding all other factors constant. Disparities associated with calculated panel‐reactive antibodies decreased sharply. Donor service area was the factor most associated with access disparities post‐KAS. This methodology will help the transplant community evaluate tradeoffs between equity and utility‐centric goals when considering new policies and help monitor equity in access as policies change.     

Combined Heart–Liver Transplantation in the MELD Era: Do Waitlisted Patients Require Exception Status?

Combined heart–liver transplant (HLT) is a viable therapy for patients with concomitant end‐stage heart and liver failure. Using data from the United Network for Organ Sharing database, we examined the cumulative incidences of transplant and mortality in waitlisted candidates for HLT, isolated heart transplant (HRT) and isolated liver transplant (LIV) in the Model for End‐Stage Liver Disease era. The incidence of waitlist mortality was higher in HLT candidates than in HRT candidates (p = 0.001, 26% vs. 12% at 1 year) or LIV candidates (p = 0.005, 26% vs. 14% at 1 year). These differences persisted after stratifying by disease severity. Posttransplant survival was not significantly different between HLT and HRT recipients or between HLT and LIV recipients. In a multivariable model, undergoing HLT was associated with enhanced survival for HLT candidates (hazard ratio, 0.41; confidence interval, 0.21–0.79; p = 0.008), but undergoing HRT alone was not. Interestingly, 90% of HLT recipients were allocated an organ locally, compared to 60% of HRT candidates and 73% of LIV candidates (both p < 0.001). These data suggest that the current cardiac and liver allocation systems may underestimate the risk of death for patients with concomitant end‐stage heart and liver failure on the HLT waitlist.     

Living kidney donors in need of kidney transplants: a report from the organ procurement and transplantation network

BACKGROUND: Our aim was to use the Organ Procurement and Transplantation Network (OPTN) database to determine the number of renal waitlist candidates who previously had been living donors. METHODS: All living renal donors in the OPTN database were cross-checked against the renal waitlist history files. Additionally, renal transplant programs were contacted that had listed candidates as qualified for four additional allocation points available to patients who previously had donated an organ. Confirmatory phone calls to transplant programs yielded additional cases previously unreported to the United Network for Organ Sharing. RESULTS: A total of 56 previous living donors were identified as having been subsequently listed for cadaveric kidney transplantation. Forty-three have received transplants; 36 currently have functioning grafts. One died after transplantation. Two candidates died while waiting. CONCLUSIONS: Living renal donation has long-term risks that may not be apparent in the short term. The numbers here reported underestimate the actual number of living donors with renal failure, because they include only patients listed for a kidney transplant. To determine risk factors for postdonation renal failure, long-term living-donor follow-up data are needed.     

Frequency of whole‐organ in lieu of split‐liver transplantation over the last decade: Children experienced increased wait time and death

Organ shortage is a barrier to liver transplantation (LT). Split LT (SLT) increases organ utilization, saving 2 recipients. A simulation of Organ Procurement and Transplantation Network/United Network for Organ Sharing data (2007‐2017) was performed to identify whole‐organ LT grafts (WLT) that met the criteria for being splittable to 2 recipients. Waitlist consequences presented. Deceased donor (DD) livers transplanted as whole organs were evaluated for suitability to split. Of these DD organs, we identified the adolescent and adult recipients of WLT who were suitable for SLT. Pediatric candidates suitable to share the SLT were ascertained from DD match‐run lists, and 1342 splittable DD organs were identified; 438 WLT recipients met the criteria for accepting a SLT. Review of the 438 DD match‐run lists identified 420 children next on the list suitable for SLT. Three hundred thirty‐three children (79%) underwent LT, but had longer wait‐times compared to 591 actual pediatric SLT recipients (median 147 days vs 44 days, P  < 0.001). Thirty‐three of 420 children died on waitlist after a mean 206 days (standard deviation 317). Sharing organs suitable for splitting increases the number of LT, saving more lives. With careful patient selection, SLT will not be a disadvantage to the adult recipients. With a children‐first allocation scheme, SLT will naturally increase the number of allografts because adult organs are too large for small children.     

Kidney,Pancreas and Liver Allocation and Distribution in the United States

Kidney transplant and liver transplant are the treatments of choice for patients with end‐stage renal disease and end‐stage liver disease, respectively. Pancreas transplant is most commonly performed along with kidney transplant in diabetic end‐stage renal disease patients. Despite a steady increase in the numbers of kidney and liver transplants performed each year in the United States, a significant shortage of kidneys and livers available for transplant remains. Organ allocation is the process the Organ Procurement and Transplantation Network (OPTN) uses to determine which candidates are offered which deceased donor organs. OPTN is charged with ensuring the effectiveness, efficiency and equity of organ sharing in the national system of organ allocation. The policy has changed incrementally over time in efforts to optimize allocation to meet these often competing goals. This review describes the history, current status and future direction of policies regarding the allocation of abdominal organs for transplant, namely the kidney, liver and pancreas, in the United States.     

Lung and Heart Allocation in the United States

Lung and heart allocation in the United States has evolved over the past 20–30 years to better serve transplant candidates and improve organ utilization. The current lung allocation policy, based on the Lung Allocation Score, attempts to take into account risk of death on the waiting list and chance of survival posttransplant. This policy is flexible and can be adjusted to improve the predictive ability of the score. Similarly, in response to the changing clinical phenotype of heart transplant candidates, heart allocation policies have evolved to a multitiered algorithm that attempts to prioritize organs to the most infirm, a designation that fluctuates with trends in therapy. The Organ Procurement and Transplantation Network and its committees have been responsive, as demonstrated by recent modifications to pediatric heart allocation and mechanical circulatory support policies and by ongoing efforts to ensure that heart allocation policies are equitable and current. Here we examine the development of US lung and heart allocation policy, evaluate the application of the current policy on clinical practice and explore future directions for lung and heart allocation.     

Risk factors for development of new-onset diabetes mellitus after transplant in adult lung transplant recipients

The objectives of this study are to examine the incidence of new-onset diabetes mellitus after transplant (NODAT) and to identify its risk factors in adult lung transplant recipients using the Organ Procurement and Transplant Network/United Network of Organ Sharing database. Between July 2004 and December 2007, a total of 3540 adults (≥18 yr old) received their first single- or double-lung transplant alone and had at least one follow-up report of post-transplant diabetic status. Among these, 2991 recipients were identified as not having diabetes mellitus (DM) pre-transplant. Risk factors for NODAT were examined. DM was newly reported in 33.4% of the 2991 recipients over the median follow-up time of 670 d. Significant independent risk factors for the development of NODAT included male gender (HR = 1.15), recipient age ≥50 (1.46), African American (1.39), higher body mass index (1.51 for ≥30 vs. 18-25), cystic fibrosis (3.30), and tacrolimus use at discharge (1.67). NODAT occurred in a third of adult lung transplant recipients during the median follow-up period. Some of the risk factors for NODAT after lung transplant are similar to those reported in other solid-organ transplants. Cystic fibrosis is a strong risk factor for development of NODAT after lung transplant.     

Fuzzy organ allocation system for cadaveric kidney transplantation

BACKGROUND: The recipient selection decision for a cadaveric donor kidney is complex and based on multiple criteria, not only medical but also ethical and political criteria. METHODS: In this study, we develop the Fuzzy Organ Allocation System (FORAS) to determine who among potential recipients receives a cadaveric kidney when it becomes available. FORAS balances various kidney allocation objectives and deals with the ambiguity and fuzziness in the allocation process. RESULTS: We used simulation to investigate how well FORAS represents the thinking of a transplant physician with regard to kidney allocation. We also compared FORAS with the United Network for Organ Sharing (UNOS) scoring system and the Turkish National Coordination for Organ Transplant (TONKS) algorithm used in Turkey. We found that FORAS well represents expert thinking in kidney allocation. CONCLUSIONS: A simulated kidney allocation experiment based on real patient and donor data showed that FORAS is more useful than other kidney allocation systems because its results more closely reflect the thinking of experienced transplant physicians.