Inferior Outcomes on the Waiting List in Low‐Volume Pediatric Heart Transplant Centers

Low case volume has been associated with poor outcomes in a wide spectrum of procedures. Our objective was to study the association of low case volume and worse outcomes in pediatric heart transplant centers, taking the novel approach of including waitlist outcomes in the analysis. We studied a cohort of 6482 candidates listed in the Organ Procurement and Transplantation Network for pediatric heart transplantation between 2002 and 2014; 4665 (72%) of the candidates underwent transplantation. Candidates were divided into groups according to the average annual transplantation volume of the listing center during the study period: more than 10, six to 10, three to five, or fewer than three transplantations. We used multivariate Cox regression analysis to identify independent risk factors for waitlist and posttransplantation mortality. Of the 6482 candidates, 24% were listed in low‐volume centers (fewer than three annual transplantations). Of these listed candidates in low‐volume centers, only 36% received a transplant versus 89% in high‐volume centers (more than 10 annual transplantations) (p < 0.001). Listing at a low‐volume center was the most significant risk factor for waitlist death (hazard ratio [HR] 4.5, 95% confidence interval [CI] 3.5–5.7 in multivariate Cox regression and HR 5.6, CI 4.4–7.3 in multivariate competing risk regression) and was significant for posttransplantation death (HR 1.27, 95% CI 1.0–1.6 in multivariate Cox regression). During the study period, one‐fourth of pediatric transplant candidates were listed in low‐volume transplant centers. These children had a limited transplantation rate and a much greater risk of dying while on the waitlist.     

Time for reform in transplant program–specific reporting: AST/ASTS transplant metrics taskforce

In accordance with the National Organ Transplant Act and Department of Health and Human Services’ Final Rule, the Scientific Registry of Transplant Recipients (SRTR) publicly releases biannual program‐specific reports that include analyses of transplant centers’ risk‐adjusted waitlist mortality, organ acceptance ratios, transplant rates, and graft and patient survival . Since the inception of these center metrics, 1‐year posttransplant graft and patient survival have improved, and center variation has decreased, casting uncertainty on their clinical relevance. The SRTR has recently modified center evaluations by ranking centers into 5 tiers rather than 3 tiers in an attempt to discriminate between programs performing within a tight range, further exacerbating this uncertainty. The American Society of Transplantation/American Society of Transplant Surgeons convened an expert taskforce to examine both the utility and unintended consequences of transplant center metrics. Estimates of center variation in outcomes in adjacent tiers are imprecise and fleeting, but can result in consequential changes in clinician and center behavior. The taskforce has concerns that current metrics, based principally on 1‐year graft and patient survival, provide minimal if any benefit in informing patient choice and access to transplantation, with the untoward effect of decreased utilization of organs and restriction of research and innovation.     

Expanding clarity or confusion? Volatility of the 5‐tier ratings assessing quality of transplant centers in the United States

Outcomes of patients receiving solid organ transplants in the United States are systematically aggregated into bi‐annual Program‐Specific Reports (PSRs) detailing risk‐adjusted survival by transplant center. Recently, the Scientific Registry of Transplant Recipients (SRTR) issued 5‐tier ratings evaluating centers based on risk‐adjusted 1‐year graft survival. Our primary aim was to examine the reliability of 5‐tier ratings over time. Using 10 consecutive PSRs for adult kidney transplant centers from June 2012 to December 2016 (n = 208), we applied 5‐tier ratings to center outcomes and evaluated ratings over time. From the baseline period (June 2012), 47% of centers had at least a 1‐unit tier change within 6 months, 66% by 1 year, and 94% by 3 years. Similarly, 46% of centers had at least a 2‐unit tier change by 3 years. In comparison, 15% of centers had a change in the traditional 3‐tier rating at 3 years. The 5‐tier ratings at 4 years had minimal association with baseline rating (Kappa 0.07, 95% confidence interval [CI] ‐0.002 to 0.158). Centers had a median of 3 different 5‐tier ratings over the period (q1 = 2, q3 = 4). Findings were consistent for center volume, transplant rate, and baseline 5‐tier rating. Cumulatively, results suggest that 5‐tier ratings are highly volatile, limiting their utility for informing potential stakeholders, particularly transplant candidates given expected waiting times between wait listing and transplantation.     

Lung Transplant Center Volume Ameliorates Adverse Influence of Prolonged Ischemic Time on Mortality

The influence of prolonged ischemic time on outcomes after lung transplant is controversial, but no research has investigated ischemic time in the context of center volume. We used data from the United Network for Organ Sharing to estimate the influence of ischemic time on patient survival conditional on center volume in the post–lung allocation score era (2005–2015). The analytic sample included 14 877 adult lung transplant recipients, of whom 12 447 were included in multivariable survival analysis. Patient survival was improved in high‐volume centers compared with low‐volume centers (log‐rank test p = 0.001), although mean ischemic times were longer at high‐volume centers (5.16 ± 1.70 h vs. 4.83 ± 1.63 h, p < 0.001). Multivariable Cox proportional hazards regression stratified by transplant center found an adverse influence of longer ischemic time at low‐volume centers but not at high‐volume centers. At centers performing 50 transplants in the period 2005–2015, for example, 8 versus 6 h of ischemia were associated with an 18.9% (95% confidence interval 6.5–32.7%; p < 0.001) greater mortality hazard, whereas at centers performing 350 transplants in this period, no differences in survival by ischemic time were predicted. Despite longer mean ischemic time at high‐volume transplant centers, these centers had favorable patient outcomes and no adverse survival implications of prolonged ischemia.     

Laparoscopic sleeve gastrectomy improves renal transplant candidacy and posttransplant outcomes in morbidly obese patients

Morbid obesity is a barrier to kidney transplantation due to inferior outcomes, including higher rates of new‐onset diabetes after transplantation (NODAT), delayed graft function (DGF), and graft failure. Laparoscopic sleeve gastrectomy (LSG) increases transplant eligibility by reducing BMI in kidney transplant candidates, but the effect of surgical weight loss on posttransplantation outcomes is unknown. Reviewing single‐center medical records, we identified all patients who underwent LSG before kidney transplantation from 2011‐2016 (n = 20). Post‐LSG kidney recipients were compared with similar‐BMI recipients who did not undergo LSG, using 2:1 direct matching for patient factors. McNemar's test and signed‐rank test were used to compare groups. Among post‐LSG patients, mean BMI ± standard deviation (SD) was 41.5 ± 4.4 kg/m² at initial encounter, which decreased to 32.3 ± 2.9 kg/m² prior to transplantation (P < .01). No complications, readmissions, or mortality occurred following LSG. After transplantation, one patient (5%) experienced DGF, and no patients experienced NODAT. Allograft and patient survival at 1‐year posttransplantation was 100%. Compared with non‐LSG patients, post‐LSG recipients had lower rates of DGF (5% vs 20%) and renal dysfunction–related readmissions (10% vs 27.5%) (P < .05 each). Perioperative complications, allograft survival, and patient survival were similar between groups. These data suggest that morbidly obese patients with end‐stage renal disease who undergo LSG to improve transplant candidacy, achieve excellent posttransplantation outcomes.     

Simulated Regionalization of Heart and Lung Transplantation in the United States

We simulated the impact of regionalization of isolated heart and lung transplantation within United Network for Organ Sharing (UNOS) regions. Overall, 12 594 orthotopic heart transplantation (OHT) patients across 135 centers and 12 300 orthotopic lung transplantation (OLT) patients across 67 centers were included in the study. An algorithm was constructed that “closed” the lowest volume center in a region and referred its patients to the highest volume center. In the unadjusted analysis, referred patients were assigned the highest volume center's 1‐year mortality rate, and the difference in deaths per region before and after closure was computed. An adjusted analysis was performed using multivariable logistic regression using recipient and donor variables. The primary outcome was the potential number of lives saved at 1 year after transplant. In adjusted OHT analysis, 10 lives were saved (95% confidence interval [CI] 9–11) after one center closure and 240 lives were saved (95% CI 209–272) after up to five center closures per region, with the latter resulting in 1624 total patient referrals (13.2% of OHT patients). For OLT, lives saved ranged from 29 (95% CI 26–32) after one center closure per region to 240 (95% CI 224–256) after up to five regional closures, but the latter resulted in 2999 referrals (24.4% of OLT patients). Increased referral distances would severely limit access to care for rural and resource‐limited populations.     

Robotic kidney transplantation in the obese patient: 10‐year experience from a single center

Despite increasing obesity rates in the dialysis population, obese kidney transplant candidates are still denied transplantation by many centers. We performed a single‐center retrospective analysis of a robotic‐assisted kidney transplant (RAKT) cohort from January 2009 to December 2018. A total of 239 patients were included in this analysis. The median BMI was 41.4 kg/m², with the majority (53.1%) of patients being African American and 69.4% of organs sourced from living donors. The median surgery duration and warm ischemia times were 4.8 hours and 45 minutes respectively. Wound complications (mostly seromas and hematomas) occurred in 3.8% of patients, with 1 patient developing a surgical site infection (SSI). Seventeen (7.1%) graft failures, mostly due to acute rejection, were reported during follow‐up. Patient survival was 98% and 95%, whereas graft survival was 98% and 93%, at 1 and 3 years respectively. Similar survival statistics were obtained from patients undergoing open transplant over the same time period from the UNOS database. In conclusion, RAKT can be safely performed in obese patients with minimal SSI risk, excellent graft function, and patient outcomes comparable to national data. RAKT could improve access to kidney transplantation in obese patients due to the low surgical complication rate.     

Pediatric heart transplantation at adult‐specialty centers in the United States: A multicenter registry analysis

Recent Organ Procurement and Transplantation Network bylaw revisions mandate that US transplant programs have an “approved pediatric component” in order to perform heart transplantation (HT) in patients <18 years old. The impact of this change on adolescents, a group known to be at high risk for graft loss and nonadherence, is unknown. We studied all US primary pediatric (age <18 years) HT from 2000 to 2015 to compare graft survival between centers organized mainly for adult versus pediatric care. Centers were designated as pediatric‐ or adult‐specialty care according to the ratio of pediatric:adult HT performed and minimum age of HT (pediatric‐specialty defined as ratio>0.7; adult‐specialty ratio<0.05 and minimum age >8 years). In propensity score‐matched cohorts, we observed no difference in graft loss by center type (median survival: adult 12.4 years vs pediatric 9.2 years, P = .174). Compared to the matched pediatric cohort, adult‐specialty center recipients lived closer to their transplant center (31 vs 45 miles, P = .012), and trended toward fewer out‐of‐state transplants (15 vs 25%, P = .082). Our data suggest that select adolescents can achieve similar midterm graft survival at centers organized primarily for adult HT care. Regardless of post‐HT setting, the development of care models that demonstrably improve adherence may be of greatest benefit to improving survival of this high‐risk population.     

Risk Assessment in High‐ and Low‐MELD Liver Transplantation

Allocation of liver grafts triggers emotional debates, as those patients, not receiving an organ, are prone to death. We analyzed a high–Model of End‐stage Liver Disease (MELD) cohort (laboratory MELD score ≥30, n = 100, median laboratory MELD score of 35; interquartile range 31–37) of liver transplant recipients at our center during the past 10 years and compared results with a low‐MELD group, matched by propensity scoring for donor age, recipient age, and cold ischemia time. End points of our study were cumulative posttransplantation morbidity, cost, and survival. Six different prediction models, including donor age x recipient MELD (D‐MELD), Difference between listing MELD and MELD at transplant (Delta MELD), donor‐risk index (DRI), Survival Outcomes Following Liver Transplant (SOFT), balance‐of‐risk (BAR), and University of California Los Angeles–Futility Risk Score (UCLA‐FRS), were applied in both cohorts to identify risk for poor outcome and high cost. All score models were compared with a clinical‐oriented decision, based on the combination of hemofiltration plus ventilation. Median intensive care unit and hospital stays were 8 and 26 days, respectively, after liver transplantation of high‐MELD patients, with a significantly increased morbidity compared with low‐MELD patients (median comprehensive complication index 56 vs. 36 points [maximum points 100] and double cost [median US$179 631 vs. US$80 229]). Five‐year survival, however, was only 8% less than that of low‐MELD patients (70% vs. 78%). Most prediction scores showed disappointing low positive predictive values for posttransplantation mortality, such as mortality above thresholds, despite good specificity. The clinical observation of hemofiltration plus ventilation in high‐MELD patients was even superior in this respect compared with D‐MELD, DRI, Delta MELD, and UCLA‐FRS but inferior to SOFT and BAR models. Of all models tested, only the BAR score was linearly associated with complications. In conclusion, the BAR score was most useful for risk classification in liver transplantation, based on expected posttransplantation mortality and morbidity. Difficult decisions to accept liver grafts in high‐risk recipients may thus be guided by additional BAR score calculation, to increase the safe use of scarce organs.     

Pediatric Liver Transplant Recipients Who Undergo Transfer to the Adult Healthcare Service Have Good Long‐Term Outcomes

Liver transplantation has transformed survival for children with liver disease necessitating the transfer of a growing number of patients to the adult healthcare service. The impact of transfer on outcomes remains unclear. The aim of this single‐center study of 137 consecutive pediatric liver transplant recipients was to examine the effect of transfer on patient and graft survival. The median time from transplant to transfer was 10.4 years and the median age of the patients at transfer was 18.6 years. After transfer, there were 5 re‐transplants and 12 deaths in 14 patients. The estimated posttransfer 10‐year patient and graft survival was 89.9% and 86.2%, respectively. Overall, 4 patients demonstrated graft loss as a consequence of chronic rejection. Graft loss was associated with older age at first transplant (p = 0.008). When compared to young adult patients transplanted in the adult center, the transferred patients did not have inferior graft survival from the point of transfer (HR 0.28; 95% CI 0.10–0.77, p = 0.014). This suggests that transfer did not impact significantly on graft longevity. In conclusion, pediatric liver transplant recipients who undergo transfer to the adult service have good long‐term outcomes.     

Impact of the new MELD‐based allocation system on waiting list and post‐transplant survival—a cohort analysis using the French national CRISTAL database

Concerns related to equity and efficacy of our previous center‐based allocation system have led us to introduce a patient‐based allocation system called the “Liver Score” that incorporates the model for end‐stage liver disease (MELD) score. The main objective of this study was to compare waitlist and post‐transplant survivals before and after implementation of the “Liver Score” using the French transplant registry (period before: 2004–2006 and period after: 2007–2012). Patients transplanted during the second period were sicker and had a higher MELD. One‐year waitlist survival (74% vs. 76%; P = 0.8) and 1‐year post‐transplant survival (86.3% vs. 85.7%; P = 0.5) were similar between the 2 periods. Cirrhotic recipients with MELD > 35 had lower 1‐year post‐transplant survival compared to those with MELD <35 (74.8% vs. 86.3%; P < 0.01), mainly explained by their higher intubation and renal failure rates. The MELD showed a poor discriminative capacity. In cirrhotic recipients with MELD > 35, patients presenting 2 or 3 risk factors (dialysis, intubation, or infection) had a lower 1‐year survival compared to those with none of these risk factors (61.2% vs. 92%; P < 0.01). The implementation of the MELD‐based allocation system has led to transplant sicker patients with no impact on waitlist and post‐transplant survivals. Nevertheless, selection of patients with MELD > 35 should be completed to allow safe transplantation.     

Under Utilization of Pancreas Transplants in Cystic Fibrosis Recipients in the United Network Organ Sharing (UNOS) Data 1987–2014

Despite a high prevalence of pancreatic endocrine and exocrine insufficiency in cystic fibrosis (CF), pancreas transplantation is rarely reported. United Network for Organ Sharing (UNOS) data were used to examine utilization of pancreas transplant and posttransplant outcomes in CF patients. Between 1987–2014, CF patients (N = 4600) underwent 17 liver–pancreas, three lung–pancreas, one liver–lung pancreas, four kidney–pancreas, and three pancreas‐only transplants. Of the 303 CF patients who received liver transplantation, 20% had CF‐related diabetes (CFRD) before transplantation, and nine of those received a liver–pancreas transplant. Of 4241 CF patients who underwent lung transplantation, 33% had CFRD before transplantation, and three of those received a pancreas transplant. Of 49 CF patients who received a liver–lung transplant, 57% had CFRD before transplantation and one received a pancreas transplant. Posttransplantation diabetes developed in 7% of CF pancreas transplant recipients versus 24% of CF liver and 29% of CF lung recipients. UNOS has no data on pancreas exocrine insufficiency. Two‐year posttransplantation survival was 88% after liver–pancreas transplant, 33% after lung–pancreas transplant, and 100% after pancreas–kidney and pancreas‐only transplants. Diabetes is common pretransplantation and posttransplantation in CF solid organ transplant recipients, but pancreas transplantation remains rare. Further consideration of pancreas transplant in CF patients undergoing other solid organ transplant may be warranted.     

Sociodemographic Determinants of Waitlist and Posttransplant Survival Among End‐Stage Liver Disease Patients

While regional organ availability dominates discussions of distribution policy, community‐level disparities remain poorly understood. We studied micro‐geographic determinants of survival risk and their distribution across Donor Service Areas (DSAs). Scientific Registry of Transplant Recipients records for all adults waitlisted for liver transplantation 2002–2014 were reviewed. The primary exposure variables were county‐level sociodemographic risk, as measured by the Community Health Score (CHS), a previously‐validated composite index local health conditions, and distance to listing transplant center. Among 114 347 patients, the median CHS was 19.4 (range: 0–40). Compared the lowest risk counties (CHS 1–10), highest‐risk counties (CHS 31–40) had more black (14.6% vs. 5.4%), publicly insured (44.9% vs. 33.0), and remote candidates (34.0% vs. 15.1% living >100 miles away). Higher‐CHS candidates had greater waitlist mortality in Cox multivariable (HR 1.16 for CHS 31–40, 95% CI 1.11–1.21) and competing risks analysis (sHR 1.07, 95% CI 0.99–1.14). Post‐transplant survival was similar across CHS quartiles. Living >25 miles from the transplant center conferred excess mortality risk (sHR 1.08, 95% CI 1.03–1.12). Proposed distribution changes would disproportionately impact DSAs with more high‐CHS or distant candidates. Low‐income, rural and minority patients experience excess mortality while awaiting transplant, and risk disproportionately worse outcomes with reduced organ availability under current proposals.     

Pancreas After Islet Transplantation: A First Report of the International Pancreas Transplant Registry

Pancreas after islet (PAI) transplantation is a treatment option for patients seeking insulin independence through a whole‐organ transplant after a failed cellular transplant. This report from the International Pancreas Transplant Registry (IPTR) and the United Network for Organ Sharing (UNOS) studied PAI transplant outcomes over a 10‐year time period. Forty recipients of a failed alloislet transplant subsequently underwent pancreas transplant alone (50%), pancreas after previous kidney transplant (22.5%), or simultaneous pancreas and kidney (SPK) transplant (27.5%). Graft and patient survival rates were not statistically significantly different compared with matched primary pancreas transplants. Regardless of the recipient category, overall 1‐ and 5‐year PAI patient survival rates for all 40 cases were 97% and 83%, respectively; graft survival rates were 84% and 65%, respectively. A failed previous islet transplant had no negative impact on kidney graft survival in the SPK category: It was the same as for primary SPK transplants. According to this IPTR/UNOS analysis, a PAI transplant is a safe procedure with low recipient mortality, high graft‐function rates in both the short and long term and excellent kidney graft outcomes. Patients with a failed islet transplant should know about this alternative in their quest for insulin independence through transplantation.     

Posttransplant outcome assessments at listing: Long‐term outcomes are more important than short‐term outcomes

Posttransplant outcome assessments are publicly reported for patient and regulatory use. However, the currently reported 1‐year posttransplant graft survival assessments are commonly criticized for not identifying clinically meaningful differences between programs, and not providing information about longer‐term posttransplant outcomes. We investigated the association of different posttransplant outcome assessments available to patients at the time of listing with subsequent posttransplant graft survival. The posttransplant assessments were from period prevalent, rather than incident, cohorts with more timely 1‐, 3‐, and 5‐year follow‐up and 6‐, 12‐, 18‐, 24‐, and 30‐month cohort windows. The association of these assessments at listing with subsequent posttransplant graft survival included candidates listed between July 12, 2011, and December 15, 2015, who subsequently underwent transplant before December 31, 2018. The assessments with 1‐year follow‐up had uniformly weaker associations than the assessments with 3‐ and 5‐year follow‐up. The assessments with 5‐year follow‐up had the strongest association in kidney and liver transplantation. For kidney, liver, and lung transplantation, assessment windows of at least 18 months typically had the strongest associations with subsequent graft survival. Posttransplant assessments with 5‐year follow‐up and 18‐30‐month cohort windows are better than the current posttransplant assessment with 1‐year follow‐up, particularly at the time of listing.     

Thoracic muscle cross‐sectional area is associated with hospital length of stay post lung transplantation: a retrospective cohort study

Low muscle mass is common in lung transplant (LTx) candidates; however, the clinical implications have not been well described. The study aims were to compare skeletal muscle mass in LTx candidates with controls using thoracic muscle cross‐sectional area (CSA) from computed tomography and assess the association with pre‐ and post‐transplant clinical outcomes. This was a retrospective, single‐center cohort study of 527 LTx candidates [median age: 55 IQR (42–62) years; 54% male]. Thoracic muscle CSA was compared to an age‐ and sex‐matched control group. Associations between muscle CSA and pre‐transplant six‐minute walk distance (6MWD), health‐related quality of life (HRQL), delisting/mortality, and post‐transplant hospital outcomes and one‐year mortality were evaluated using multivariable regression analysis. Muscle CSA for LTx candidates was about 10% lower than controls (n = 38). Muscle CSA was associated with pre‐transplant 6MWD, but not HRQL, delisting or pre‐ or post‐transplant mortality. Muscle CSA (per 10 cm² difference) was associated with shorter hospital stay [0.7 median days 95% CI (0.2–1.3)], independent of 6MWD. In conclusion, thoracic muscle CSA is a simple, readily available estimate of skeletal muscle mass predictive of hospital length of stay, but further study is needed to evaluate the relative contribution of muscle mass versus functional deficits in LTx candidates.     

Incidence,characterization, and impact of newly detected donor‐specific anti‐HLA antibody in the first year after pediatric heart transplantation: A report from the CTOTC‐04 study

Data on the clinical importance of newly detected donor‐specific anti‐HLA antibodies (ndDSAs) after pediatric heart transplantation are lacking despite mounting evidence of the detrimental effect of de novo DSAs in solid organ transplantation. We prospectively tested 237 pediatric heart transplant recipients for ndDSAs in the first year posttransplantation to determine their incidence, pattern, and clinical impact. One‐third of patients developed ndDSAs; when present, these were mostly detected within the first 6 weeks after transplantation, suggesting that memory responses may predominate over true de novo DSA production in this population. In the absence of preexisting DSAs, patients with ndDSAs had significantly more acute cellular rejection but not antibody‐mediated rejection, and there was no impact on graft and patient survival in the first year posttransplantation. Risk factors for ndDSAs included common sensitizing events. Given the early detection of the antibody response, memory responses may be more important in the first year after pediatric heart transplantation and patients with a history of a sensitizing event may be at risk even with a negative pretransplantation antibody screen. The impact on late graft and patient outcomes of first‐year ndDSAs is being assessed in an extended cohort of patients.     

A Transplant‐Specific Quality Initiative–Introducing TransQIP: A Joint Effort of the ASTS and ACS

In an attempt to improve surgical quality in the field of transplantation, the American College of Surgeons (ACS) and American Society of Transplant Surgeons have initiated a national quality improvement program in transplantation. This transplant‐specific quality improvement program, called TransQIP, has been built from the ground up by transplant surgeons and captures detailed information on donor and recipient factors as well as transplant‐specific outcomes. It is built upon the existing ACS/National Surgical Quality Improvement Program infrastructure and is designed to capture 100% of liver and kidney transplants performed at participating sites. TransQIP has completed its alpha pilot and will embark upon its beta phase at approximately 30 centers in the spring of 2017. Going forward, we anticipate TransQIP will help satisfy Centers for Medicare and Medicaid Services requirements for a quality improvement program, surgeon requirements for maintenance of certification, and qualify as a clinical practice improvement activity under the Merit‐Based Incentive Payment System. Most importantly, we believe TransQIP will provide insight into surgical outcomes in transplantation that will allow the field to provide better care to our patients .     

Five‐Year Outcomes in Living Donor Kidney Transplants With a Positive Crossmatch

Renal transplant candidates with high levels of donor‐specific anti‐HLA antibodies have low transplantation rates and high mortality rates on dialysis. Using desensitization protocols, good short‐term outcomes are possible in “positive crossmatch kidney transplants (+XMKTx)”, but long‐term outcome data are lacking. The aim of the current study was to determine actual 5‐year graft outcomes of +XMKTx. We compared graft survival and the functional and histologic status of 102 +XMKTx to 204 ?XMKTx matched for age and sex. Actual 5‐year death‐censored graft survival was lower in the +XMKTx group (70.7% vs. 88.0%, p < 0.01) and chronic injury (glomerulopathy) was present in 54.5% of surviving grafts. Graft survival was higher in recipients with antibody against donor class I only compared with antibody against class II (either alone or in combination with class I) (85.3% vs. 62.6%, p = 0.05) and was similar to ?XMKTx (85.3 vs. 88.0%, p = 0.64). Renal function and proteinuria ranged across a wide spectrum in all groups reflecting the different histological findings at 5 years. We conclude that when compared to ?XMKTx, +XMKTx have inferior outcomes at 5 years, however, almost half of the surviving grafts do not have glomerulopathy and avoiding antibodies against donor class II may improve outcomes.     

Rates of False Flagging Due to Statistical Artifact in CMS Evaluations of Transplant Programs: Results of a Stochastic Simulation

The recent CMS conditions of participation are based on risk‐adjusted models produced by the Scientific Registry for Transplant Recipients (SRTR). The accuracy of these models in identifying poor‐performing centers is unknown. In this stochastic simulation study, 1‐year mortality outcomes were simulated in virtual transplant centers, and used to flag centers according to the methods used by CMS, evaluating nine overlapping 2.5‐year periods of simulated data. In a simulation where all centers had the same underlying risk, 10.2% were falsely flagged at least once during the 4.5 years of simulated evaluations. The probability of false‐positive flagging was lowest in low‐volume centers (2.5%) and highest in high‐volume centers (16.2%). In another simulation where 5% of centers were assigned twofold risk (“poor‐performing centers”), only 32% of poor‐performing centers were correctly flagged. In a final simulation where each center was assigned a unique mortality risk, 94% of flagged centers had greater‐than‐median risk, but only 32% of flagged centers were among the 5% with highest risk. Even after disregarding known covariate limitations to the risk adjustment models, statistical noise alone leads to spurious flagging of many adequately‐performing transplant centers, yet the methods used by CMS fail to flag most centers with true elevated risk.