Declined Offers for Deceased Donor Kidneys Are Not an Independent Reflection of Organ Quality

Background

Deceased donor kidney offers are frequently declined multiple times before acceptance for transplantation, despite significant organ shortage and long waiting times. Whether the number of times a kidney has been declined, reflecting cumulative judgments of clinicians, is associated with long-term transplant outcomes remains unclear.

Methods

In this national, retrospective cohort study of deceased donor kidney transplants in the United States from 2008 to 2015 (n=78,940), we compared donor and recipient characteristics and short- and long-term graft and patient survival outcomes grouping by the sequence number at which the kidney was accepted for transplantation. We compared outcomes for kidneys accepted within the first seven offers in the match-run, after 8-100 offers, and for hard-to-place kidneys distinguishing those requiring >100 and >1000 offers before acceptance.

Results

Harder-to-place kidneys had lower donor quality and higher rates of delayed graft function (46% among kidneys requiring >1000 offers before acceptance versus 23% among kidneys with ≤7 offers). In unadjusted models, later sequence groups had higher hazard of all-cause graft failure, death-censored graft failure, and patient mortality; however, these associations were attenuated after adjusting for Kidney Donor Risk Index (KDRI). After adjusting for donor factors already taken into consideration during allocation, and recipient factors associated with long-term outcomes, graft, and patient survival outcomes were not significantly different for the hardest-to-place kidneys compared with the easiest-to-place kidneys, with the exception of death-censored graft failure (adjusted hazard ratio, 1.16, 95% CI, 1.05 to 1.28).

Conclusion

Late sequence offers may represent missed opportunities for earlier successful transplant for the higher-priority waitlisted candidates for whom the offers were declined.

COVID-19-Associated Mortality among Kidney Transplant Recipients and Candidates in the United States

BACKGROUND AND OBJECTIVES

The coronavirus disease 2019 (COVID-19) pandemic has had a profound effect on transplantation activity in the United States and globally. Several single-center reports suggest higher morbidity and mortality among candidates waitlisted for a kidney transplant and recipients of a kidney transplant. We aim to describe 2020 mortality patterns during the COVID-19 pandemic in the United States among kidney transplant candidates and recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using national registry data for waitlisted candidates and kidney transplant recipients collected through April 23, 2021, we report demographic and clinical factors associated with COVID-19-related mortality in 2020, other deaths in 2020, and deaths in 2019 among waitlisted candidates and transplant recipients. We quantify excess all-cause deaths among candidate and recipient populations in 2020 and deaths directly attributed to COVID-19 in relation to prepandemic mortality patterns in 2019 and 2018.

RESULTS

Among deaths of patients who were waitlisted in 2020, 11% were attributed to COVID-19, and these candidates were more likely to be male, obese, and belong to a racial/ethnic minority group. Nearly one in six deaths (16%) among active transplant recipients in the United States in 2020 was attributed to COVID-19. Recipients who died of COVID-19 were younger, more likely to be obese, had lower educational attainment, and were more likely to belong to racial/ethnic minority groups than those who died of other causes in 2020 or 2019. We found higher overall mortality in 2020 among waitlisted candidates (24%) than among kidney transplant recipients (20%) compared with 2019.

CONCLUSIONS

Our analysis demonstrates higher rates of mortality associated with COVID-19 among waitlisted candidates and kidney transplant recipients in the United States in 2020.

Variations in deceased donor kidney procurement biopsy practice patterns: A survey of U.S. organ procurement organizations

BACKGROUND

Procurement biopsies have become a common practice in the evaluation and allocation of deceased donor kidneys in the United States despite questions about their value and reproducibility. We sought to determine the extent of OPO-level differences in criteria used to decide which deceased donor kidneys undergo a procurement biopsy and to assess the degree of variability in procurement biopsy technique and interpretation across OPOs.

METHODS

Each of the country's 58 OPOs were invited to participate in the survey. OPOs were divided into two groups based on organ availability ratio and deceased donor kidney discard rate.

RESULTS AND CONCLUSIONS

Fifty-out-of-fifty-eight invited OPOs (86% response rate) responded to the survey between November 2020 and December 2020. Thirty (60%) OPOs reported that they have formal criteria for performing kidney procurement biopsy, but for 29 of these OPOs, transplant centers can request biopsy on kidneys that do not meet criteria. OPOs used a total of seven different variables and 12 different numerical thresholds to define impaired kidney function that would prompt a procurement biopsy. Additionally, wide variability was seen in biopsy technique and procedures for biopsy interpretation and reporting of findings to transplant programs. These findings identify a clear opportunity for standardization of procurement biopsies to best practices.

COVID-19 mortality among kidney transplant candidates is strongly associated with social determinants of health

The COVID-19 pandemic has affected all portions of the global population. However, many factors have been shown to be particularly associated with COVID-19 mortality including demographic characteristics, behavior, comorbidities, and social conditions. Kidney transplant candidates may be particularly vulnerable to COVID-19 as many are dialysis-dependent and have comorbid conditions. We examined factors associated with COVID-19 mortality among kidney transplant candidates from the National Scientific Registry of Transplant Recipients from March 1 to December 1, 2020. We evaluated crude rates and multivariable incident rate ratios (IRR) of COVID-19 mortality. There were 131 659 candidates during the study period with 3534 all-cause deaths and 384 denoted a COVID-19 cause (5.00/1000 person years). Factors associated with increased COVID-19 mortality included increased age, males, higher body mass index, and diabetes. In addition, Blacks (IRR = 1.96, 95% C.I.: 1.43-2.69) and Hispanics (IRR = 3.38, 95% C.I.: 2.46-4.66) had higher COVID-19 mortality relative to Whites. Patients with lower educational attainment, high school or less (IRR = 1.93, 95% C.I.: 1.19-3.12, relative to post-graduate), Medicaid insurance (IRR = 1.73, 95% C.I.: 1.26-2.39, relative to private), residence in most distressed neighborhoods (fifth quintile IRR = 1.93, 95% C.I.: 1.28-2.90, relative to first quintile), and most urban and most rural had higher adjusted rates of COVID-19 mortality. Among kidney transplant candidates in the United States, social determinants of health in addition to demographic and clinical factors are significantly associated with COVID-19 mortality.

Perspectives on COVID-19 vaccination among kidney and pancreas transplant recipients living in New York City

Purpose

Solid organ transplant recipients are at increased risk of morbidity and mortality from coronavirus disease 2019 (COVID-19), but limited vaccine access and vaccine hesitancy can complicate efforts for expanded vaccination. We report patient perspectives and outcomes from a vaccine outreach initiative for a vulnerable population of transplant recipients living in New York City.

Methods

This was a retrospective review of qualitative perspectives from a COVID-19 vaccine outreach initiative. In the outreach effort, kidney and pancreas transplant recipients under care at the transplant center at NewYork-Presbyterian Hospital were initially contacted electronically with educational material about vaccination followed by telephone outreach to eligible unvaccinated patients. Calls were used to schedule vaccine appointments for patients who agreed, answer questions, and assess attitudes and concerns for patients not yet ready to be vaccinated, with conversational themes recorded.

Results

Of the 1,078 patients living in the 5 New York City boroughs who had not reported receiving COVID-19 vaccination, 320 eligible patients were contacted by telephone. Of these, 210 patients were scheduled for vaccination at our vaccine site (including 13 who agreed to vaccination after initially declining), while 110 patients were either not ready or not interested in being vaccinated. The total number of patients willing to be vaccinated was 554 when also including those already vaccinated. Unwillingness to be vaccinated was associated with younger age (median age of 47 vs 60 years, P < 0.001), Black race (P = 0.004), and residence in Bronx or Brooklyn counties (P = 0.018) or a zip code with a medium level of poverty (P = 0.044). The most common issues raised by patients who were ambivalent or not interested in vaccination were regarding unknown safety of the vaccines in general, a belief that there was a lack of data about the vaccines in transplant recipients, and a lack of trust in the scientific process underlying vaccine development, with 34% of the patients contacted expressing vaccine hesitancy overall.

Conclusion

Our qualitative summary identifies determinants of COVID-19 vaccine hesitancy in a diverse transplant patient population, supporting the need for transplant centers to implement tailored interventions to increase vaccine acceptance in this vulnerable population.

Association between procurement biopsy findings and deceased donor kidney outcomes: a paired kidney analysis

Unfavourable procurement biopsy findings are the most common reason for deceased donor kidney discard in the United States. We sought to assess the association between biopsy findings and post-transplant outcomes when donor characteristics are accounted for. We used registry data to identify 1566 deceased donors of 3132 transplanted kidneys (2015-2020) with discordant right/left procurement biopsy classification and performed time-to-event analyses to determine the association between optimal histology and hazard of death-censored graft failure or death. We then repeated all analyses using a local cohort of 147 donors of kidney pairs with detailed procurement histology data available (2006-2016). Among transplanted kidney pairs in the national cohort, there were no significant differences in incidence of delayed graft function or primary nonfunction. Time to death-censored graft failure was not significantly different between recipients of optimal versus suboptimal kidneys. Results were similar in analyses using the local cohort. Regarding recipient survival, analysis of the national, but not local, cohort showed optimal kidneys were associated with a lower hazard of death (adjusted HR 0.68, 95% CI 0.52-0.90, P = 0.006). In conclusion, in a large national cohort of deceased donor kidney pairs with discordant right/left procurement biopsy findings, we found no association between histology and death-censored graft survival.

Greater complexity and monitoring of the new Kidney Allocation System: Implications and unintended consequences of concentric circle kidney allocation on network complexity

The deceased donor kidney allocation system in the United States has undergone several rounds of iterative changes, but these changes were not explicitly designed to address the geographic variation in access to transplantation. The new allocation system, expected to start in December 2020, changes the definition of "local allocation" from the Donation Service Area to 250 nautical mile circles originating from the donor hospital. While other solid organs have adopted a similar approach, the larger number of both kidney transplant centers and transplant candidates is likely to have different consequences. Here, we discuss the incredible increase in complexity in allocation, discuss some of the likely intended and unintended consequences, and propose metrics to monitor the new system.

Association Between Donor-Recipient Biological Relationship and Allograft Outcomes After Living Donor Kidney Transplant

IMPORTANCE

The proportion of living donor kidney transplants from donors unrelated to their recipients is increasing in the US.

OBJECTIVE

To examine the association between donor-recipient biological relationship and allograft survival after living donor kidney transplant.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used Organ Procurement and Transplantation Network data on US adult living donor kidney transplants (n = 86 154) performed from January 1, 2000, to December 31, 2014, excluding cases in which recipients previously received a kidney transplant (n = 10 342) or key data were missing (n = 2832). Last follow-up was March 20, 2020.

EXPOSURES

Donor-recipient biological relationship.

MAIN OUTCOMES AND MEASURES

The primary outcome was death-censored allograft failure. Univariate and multivariable time-to-event analyses were performed for death-censored allograft failure for the overall cohort, then separately for recipients with and without primary diagnoses of cystic kidney disease and for transplants from African American and non-African American donors.

RESULTS

Among the 72 980 transplant donor and recipients included in the study (median donor age, 41 years; interquartile range [IQR], 32-50 years; 43 990 [60%] female; 50 014 [69%] White), 43 174 (59%) donors and recipients were biologically related and 29 806 (41%) were unrelated. Donors related to their recipients were younger (median [IQR] age, 39 [31-48] vs 44 [35-52] years) and less likely to be female (24 848 [58%] vs 19 142 [64%]) or White (26 933 [62%] vs 23 081 [77%]). Recipients related to their donors were younger (median [IQR] age, 48 [34-58] vs 50 [40-58] years), more likely to be female (18 035 [42%] vs 10 530 [35%]), and less likely to have cystic kidney disease (2530 [6%] vs 4600 [15%]). Related pairs had fewer HLA mismatches overall (median [IQR], 3 [2-3] vs 5 [4-5]). After adjustment for HLA mismatches, donor and recipient characteristics, and transplant era, donor-recipient biological relationship was associated with higher death-censored allograft failure (hazard ratio, 1.05; 95% CI, 1.01-1.10; P = .03). When stratified by primary disease, this association persisted only for recipients without cystic kidney disease. When stratified by donor race, this association persisted only for transplants from African American donors.

CONCLUSIONS AND RELEVANCE

In this cohort study, living donor kidney transplants from donors biologically related to their recipients had higher rates of allograft failure than transplants from donors unrelated to their recipients after HLA matching was accounted for. Further study is needed to determine which genetic or socioenvironmental factors are associated with this finding.

Left-digit bias and deceased donor kidney utilization

Cognitive biases shown to impact medical decision-making include left-digit bias, the tendency to focus on a continuous variable's leftmost digit. We hypothesized that left-digit bias impacts deceased donor kidney utilization through heuristic processing of donor age and creatinine. We used US registry data to identify 87 019 kidneys recovered (2015-2019) and compared the proportion around thresholds for donor age (69 vs. 70 years) and creatinine (1.9 vs. 2.0 mg/dl), then compared the risk of kidney discard. Kidneys from donors aged 70 vs. 69 years were more frequently discarded (77% vs. 65%, p < .001), with higher risk of discard even after adjusting for KDRI (adjusted RR 1.11, 95% CI 1.02-1.21, p = .018). Similarly, kidneys from donors with final creatinine 2.0 vs. 1.9 mg/dl were more frequently discarded (37% vs. 29%, p < .001), with higher risk of discard after adjusting for KDRI (adjusted RR 1.19, 95% CI 1.07-1.33, p = .001). However, no significant left-digit effect was found when examining other donor age (39/40, 49/50, 59/60 years) or creatinine (0.9/1.0, 2.9/3.0 mg/dl) thresholds. The findings suggest a possible left-digit effect affecting kidney utilization at specific thresholds. Additional investigations of the impact of this and other heuristics on organ utilization are needed to identify potential areas for decision-making interventions aimed at reducing kidney discard.

Racial disparities in preemptive waitlisting and deceased donor kidney transplantation: Ethics and solutions

Kidney transplantation prior to dialysis, known as "preemptive transplant," enables patients to live longer and avoid the substantial quality of life burdens due to chronic dialysis. Deceased donor kidneys are a public resource that ought to provide health benefits equitably. Unfortunately, White, better educated, and privately insured patients enjoy disproportionate access to preemptive transplantation using deceased donor kidneys. This problem has persisted for decades and is exacerbated by the first-come, first-served approach to kidney allocation for predialysis patients. In this Personal Viewpoint, we describe the diverse barriers to preemptive waitlisting and kidney transplant. The analysis focuses on healthcare system features that particularly disadvantage Black patients, such as the waitlisting eligibility criterion of a single glomerular filtration rate or creatinine clearance ≤20 ml/min, and neglect of wide variation in the rate of progression to end-stage kidney disease (ESKD) in allocating preemptive transplants. We propose initiatives to improve equity including: (1) standardization of waitlisting eligibility criteria related to kidney function; (2) aggressive education for clinicians about early transplant referral; (3) innovations in electronic medical record capabilities; and (4) rapid status 7 listing by centers. If those initiatives fail, the transplant field should consider eliminating preemptive waitlisting and transplantation with deceased donor kidneys.

High rate of renal recovery in survivors of COVID-19 associated acute renal failure requiring renal replacement therapy

INTRODUCTION

A large proportion of patients with COVID-19 develop acute kidney injury (AKI). While the most severe of these cases require renal replacement therapy (RRT), little is known about their clinical course.

METHODS

We describe the clinical characteristics of COVID-19 patients in the ICU with AKI requiring RRT at an academic medical center in New York City and followed patients for outcomes of death and renal recovery using time-to-event analyses.

RESULTS

Our cohort of 115 patients represented 23% of all ICU admissions at our center, with a peak prevalence of 29%. Patients were followed for a median of 29 days (2542 total patient-RRT-days; median 54 days for survivors). Mechanical ventilation and vasopressor use were common (99% and 84%, respectively), and the median Sequential Organ Function Assessment (SOFA) score was 14. By the end of follow-up 51% died, 41% recovered kidney function (84% of survivors), and 8% still needed RRT (survival probability at 60 days: 0.46 [95% CI: 0.36-0.56])). In an adjusted Cox model, coronary artery disease and chronic obstructive pulmonary disease were associated with increased mortality (HRs: 3.99 [95% CI 1.46-10.90] and 3.10 [95% CI 1.25-7.66]) as were angiotensin-converting-enzyme inhibitors (HR 2.33 [95% CI 1.21-4.47]) and a SOFA score >15 (HR 3.46 [95% CI 1.65-7.25).

CONCLUSIONS AND RELEVANCE

Our analysis demonstrates the high prevalence of AKI requiring RRT among critically ill patients with COVID-19 and is associated with a high mortality, however, the rate of renal recovery is high among survivors and should inform shared-decision making.

Major Variation across Local Transplant Centers in Probability of Kidney Transplant for Wait-Listed Patients

BACKGROUND

Geographic disparities in access to deceased donor kidney transplantation persist in the United States under the Kidney Allocation System (KAS) introduced in 2014, and the effect of transplant center practices on the probability of transplantation for wait-listed patients remains unclear.

METHODS

To compare probability of transplantation across centers nationally and within donation service areas (DSAs), we conducted a registry study that included all United States incident adult kidney transplant candidates wait listed in 2011 and 2015 (pre-KAS and post-KAS cohorts comprising 32,745 and 34,728 individuals, respectively). For each center, we calculated the probability of deceased donor kidney transplantation within 3 years of wait listing using competing risk regression, with living donor transplantation, death, and waiting list removal as competing events. We examined associations between center-level and DSA-level characteristics and the adjusted probability of transplant.

RESULTS

Candidates received deceased donor kidney transplants within 3 years of wait listing more frequently post-KAS (22%) than pre-KAS (19%). Nationally, the probability of transplant varied 16-fold between centers, ranging from 4.0% to 64.2% in the post-KAS era. Within DSAs, we observed a median 2.3-fold variation between centers, with up to ten-fold and 57.4 percentage point differences. Probability of transplantation was correlated in the post-KAS cohort with center willingness to accept hard-to-place kidneys (r=0.55, P<0.001) and local organ supply (r=0.44, P<0.001).

CONCLUSIONS

Large differences in the adjusted probability of deceased donor kidney transplantation persist under KAS, even between centers working with the same local organ supply. Probability of transplantation is significantly associated with organ offer acceptance patterns at transplant centers, underscoring the need for greater understanding of how centers make decisions about organs offered to wait-listed patients and how they relate to disparities in access to transplantation.

Rule Out Acute Kidney Injury in the Emergency Department With a Urinary Dipstick

Introduction

The identification of acute injury of the kidney relies on serum creatinine (SCr), a functional marker with poor temporal resolution as well as limited sensitivity and specificity for cellular injury. In contrast, urinary biomarkers of kidney injury have the potential to detect cellular stress and damage in real time.

Methods

To detect the response of the kidney to injury, we have tested a lateral flow dipstick that measures a urinary protein called neutrophil gelatinase-associated lipocalin (NGAL). Analysis of urine was performed in a prospective cohort of 479 patients (final cohort N = 426) entering an emergency department in New York City and subsequently admitted for inpatient care.

Results

Colorimetric development had high interrater reliability (88% concordance rate) and correlated with traditional enzyme-linked immunosorbent assay (ELISA) measurements (ρ = 0.732, P < .0001). Of the 14% of the cohort who met Acute Kidney Injury Network (AKIN) SCr criteria for acute kidney injury (AKI), 67% demonstrated transient (<2 days) and 33% demonstrated sustained (>2 days) elevation of SCr. Comparing the outcomes of patients with sustained versus transient or undetectable changes in SCr revealed that the urinary NGAL (uNGAL) dipstick had high specificity and negative predictive value (NPV) (high- vs. low-intermediate readings, sensitivity = 0.55, specificity = 0.91, positive predictive value = 0.24, NPV = 0.97, χ² = 20.39, P < 0.001).

Conclusion

We show that the introduction of a bedside uNGAL dipstick permits accurate triage by identifying individuals who do not have tubular injury. In an era of shortening length of stay and rapid decisions based on isolated SCr measurements, real-time exclusion of kidney injury by a dipstick will be particularly useful to overcome the retrospective, insensitive, and nonspecific attributes of SCr.

Impact of Deceased Donor Kidney Procurement Biopsy Technique on Histologic Accuracy

Introduction

The factors that influence deceased donor kidney procurement biopsy reliability are not well established. We examined the impact of biopsy technique and pathologist training on procurement biopsy accuracy.

Methods

We retrospectively identified all deceased donor kidney-only transplants at our center from 2006 to 2016 with both procurement and reperfusion biopsies performed and information available on procurement biopsy technique and pathologist (n = 392). Biopsies were scored using a previously validated system, classifying “suboptimal” histology as the presence of at least 1 of the following: glomerulosclerosis ≥11%, moderate/severe interstitial fibrosis/tubular atrophy, or moderate/severe vascular disease. We calculated relative risk ratios (RRR) to determine the influence of technique (core vs. wedge) and pathologist (renal vs. nonrenal) on concordance between procurement and reperfusion biopsy histologic classification.

Results

A total of 171 (44%) procurement biopsies used wedge technique, and 221 (56%) used core technique. Results of only 36 biopsies (9%) were interpreted by renal pathologists. Correlation between procurement and reperfusion glomerulosclerosis was poor for both wedge (r² = 0.11) and core (r² = 0.14) biopsies. Overall, 34% of kidneys had discordant classification on procurement versus reperfusion biopsy. Neither biopsy technique nor pathologist training was associated with concordance between procurement and reperfusion histology, but a larger number of sampled glomeruli was associated with a higher likelihood of concordance (adjusted RRR = 1.12 per 10 glomeruli, 95% confidence interval = 1.04−1.22).

Conclusions

Biopsy technique and pathologist training were not associated with procurement biopsy histologic accuracy in this retrospective study. Prospective trials are needed to determine how to optimize procurement biopsy practices.

Outcomes for Patients With COVID-19 and Acute Kidney Injury: A Systematic Review and Meta-Analysis

INTRODUCTION

There are limited data on the association of kidney dysfunction with prognosis in coronavirus disease 2019 (COVID-19), and the extent to which acute kidney injury (AKI) predisposes patients to severe illness and inferior outcomes is unclear. We aim to assess the incidence of AKI among patients with COVID-19 and examine their associations with patient outcomes as reported in the available literature thus far.

METHODS

We systematically searched MEDLINE, EMBASE, SCOPUS, and MedRxiv databases for full-text articles available in English published from December 1, 2019 to May 24, 2020. Clinical information was extracted and examined from 20 cohorts that met inclusion criteria, covering 13,137 mostly hospitalized patients confirmed to have COVID-19. Two authors independently extracted study characteristics, results, outcomes, study-level risk of bias, and strength of evidence across studies. Neither reviewer was blind to journal titles, study authors, or institutions.

RESULTS

Median age was 56 years, with 55% male patients. Approximately 43% of patients had severe COVID-19 infection, and approximately 11% died. Prevalence of AKI was 17%; 77% of patients with AKI experienced severe COVID-19 infection, and 52% died. AKI was associated with increased odds of death among COVID-19 patients (pooled odds ratio, 15.27; 95% CI 4.82-48.36), although there was considerable heterogeneity across studies and among different regions in the world. Approximately 5% of all patients required use of renal replacement therapy (RRT).

CONCLUSIONS

Kidney dysfunction is common among patients with COVID-19, and patients who develop AKI have inferior outcomes. Additional research into management and potential mechanisms of this association is needed.

Impact of warm ischemia time on outcomes for kidneys donated after cardiac death Post-KAS

Prolonged warm (WIT) and cold (CIT) ischemia times are often important considerations in the discard of DCD kidneys, but their impact on post-transplant outcomes in the post-KAS era is unclear. We examined the association of ischemia time on delayed graft function (DGF) and death-censored graft failure for DCD kidneys. The 2018 SRTR SAF was utilized to identify post-KAS DCD kidney transplants occurring from 2015 to 2018. Relative risk and Cox regression were used to calculate risk of delayed graft function and hazard of death-censored graft failure, respectively. We identified 4,680 kidneys from DCD donors transplanted from 2015 to 2018 with recorded WIT and CIT times. Median WIT was 21.0 minutes (IQR 14.0-28.0), and CIT was 18.5 hours (IQR 13.9-23.5). The overall incidence of DGF was 42.7%. In a univariable relative risk regression model, extended CIT (24-30 hours:RR 1.37, 95% CI 1.15-1.77; >30 hours:RR 1.47, 95% CI 1.22-1.77) and WIT (20-40 minutes:RR 1.10, 95% CI 1.03-1.17) were associated with increased risk of DGF. When included in a multivariable model, neither prolonged CIT nor WIT were significantly associated with death-censored graft failure. Prolonged WIT and CIT are associated with increased DGF but not death-censored graft failure in recipients of DCD kidney transplants in the post-KAS era. Extended ischemia alone should not be used as a basis for discard or non-utilization of these organs.

Financial impact of delayed graft function in kidney transplantation

Increased utilization of suboptimal organs in response to organ shortage has resulted in increased incidence of delayed graft function (DGF) after transplantation. Although presumed increased costs associated with DGF are a deterrent to the utilization of these organs, the financial burden of DGF has not been established. We used the Premier Healthcare Database to conduct a retrospective analysis of healthcare resource utilization and costs in kidney transplant patients (n = 12 097) between 1/1/2014 and 12/31/2018. We compared cost and hospital resource utilization for transplants in high-volume (n = 8715) vs low-volume hospitals (n = 3382), DGF (n = 3087) vs non-DGF (n = 9010), and recipients receiving 1 dialysis (n = 1485) vs multiple dialysis (n = 1602). High-volume hospitals costs were lower than low-volume hospitals ($103 946 vs $123 571, P < .0001). DGF was associated with approximately $18 000 (10%) increase in mean costs ($130 492 vs $112 598, P < .0001), 6 additional days of hospitalization (14.7 vs 8.7, P < .0001), and 2 additional ICU days (4.3 vs 2.1, P < .0001). Multiple dialysis sessions were associated with an additional $10 000 compared to those with only 1. In conclusion, DGF is associated with increased costs and length of stay for index kidney transplant hospitalizations and payment schemes taking this into account may reduce clinicians' reluctance to utilize less-than-ideal kidneys.

Reproducibility of Deceased Donor Kidney Procurement Biopsies

BACKGROUND AND OBJECTIVES

Unfavorable histology on procurement biopsies is the most common reason for deceased donor kidney discard. We sought to assess the reproducibility of procurement biopsy findings.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We compiled a continuous cohort of deceased donor kidneys transplanted at our institution from 1/1/2006 to 12/31/2016 that had at least one procurement biopsy performed, and excluded cases with missing biopsy reports and those used in multiorgan transplants. Suboptimal histology was defined as the presence of advanced sclerosis in greater than or equal to one biopsy compartment (glomeruli, tubules/interstitium, vessels). We calculated κ coefficients to assess agreement in optimal versus suboptimal classification between sequential biopsy reports for kidneys that underwent multiple procurement biopsies and used time-to-event analysis to evaluate the association between first versus second biopsies and patient and allograft survival.

RESULTS

Of the 1011 kidneys included in our cohort, 606 (60%) had multiple procurement biopsies; 98% had first biopsy performed at another organ procurement organization and their second biopsy performed locally. Categorical agreement was highest for vascular disease (κ=0.17) followed by interstitial fibrosis and tubular atrophy (κ=0.12) and glomerulosclerosis (κ=0.12). Overall histologic agreement (optimal versus suboptimal) was κ=0.15. First biopsy histology had no association with allograft survival in unadjusted or adjusted analyses. However, second biopsy optimal histology was associated with a higher probability of death-censored allograft survival, even after adjusting for donor and recipient factors (adjusted hazard ratio, 0.50; 95% confidence interval, 0.34 to 0.75; P=0.001).

CONCLUSIONS

Deceased donor kidneys that underwent multiple procurement biopsies often displayed substantial differences in histologic categorization in sequential biopsies, and there was no association between first biopsy findings and post-transplant outcomes.

A Donor Utilization Index to Assess the Utilization and Discard of Deceased Donor Kidneys Perceived as High Risk

BACKGROUND AND OBJECTIVES

An increasing number of patients on the waitlist for a kidney transplant indicates a need to effectively utilize as many deceased donor kidneys as possible while ensuring acceptable outcomes. Assessing regional and center-level organ utilization with regards to discard can reveal regional variation in suboptimal deceased donor kidney acceptance patterns stemming from perceptions of risk.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We created a weighted donor utilization index from a logistic regression model using high-risk donor characteristics and discard rates from 113,640 deceased donor kidneys procured for transplant from 2010 to 2016, and used it to examine deceased donor kidney utilization in 182 adult transplant centers with >15 annual deceased donor kidney transplants. Linear regression and correlation were used to analyze differences in donor utilization indexes.

RESULTS

The donor utilization index was found to significantly vary by Organ Procurement and Transplantation Network region (P<0.001), revealing geographic trends in kidney utilization. When investigating reasons for this disparity, there was no significant correlation between center volume and donor utilization index, but the percentage of deceased donor kidneys imported from other regions was significantly associated with donor utilization for all centers (rho=0.39; P<0.001). This correlation was found to be particularly strong for region 4 (rho=0.83; P=0.001) and region 9 (rho=0.82; P=0.001). Additionally, 25th percentile time to transplant was weakly associated with the donor utilization index (R ²=0.15; P=0.03).

CONCLUSIONS

There is marked center-level variation in the use of deceased donor kidneys with less desirable characteristics both within and between regions. Broader utilization was significantly associated with shorter time to transplantation.

Trends in Disparities in Preemptive Kidney Transplantation in the United States

BACKGROUND AND OBJECTIVES

Long wait times for deceased donor kidneys and low rates of preemptive wait-listing have limited preemptive transplantation in the United States. We aimed to assess trends in preemptive deceased donor transplantation with the introduction of the new Kidney Allocation System (KAS) in 2014 and identify whether key disparities in preemptive transplantation have changed.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified adult deceased donor kidney transplant recipients in the United States from 2000 to 2018 using the Scientific Registry of Transplant Recipients. Preemptive transplantation was defined as no dialysis before transplant. Associations between recipient, donor, transplant, and policy era characteristics and preemptive transplantation were calculated using logistic regression. To test for modification by KAS policy era, an interaction term between policy era and each characteristic of interest was introduced in bivariate and adjusted models.

RESULTS

The proportion of preemptive transplants increased after implementation of KAS from 9.0% to 9.8%, with 1.10 (95% confidence interval [95% CI], 1.06 to 1.14) times higher odds of preemptive transplantation post-KAS compared with pre-KAS. Preemptive recipients were more likely to be white, older, female, more educated, hold private insurance, and have ESKD cause other than diabetes or hypertension. Policy era significantly modified the association between preemptive transplantation and race, age, insurance status, and Human Leukocyte Antigen zero-mismatch (interaction P<0.05). Medicare patients had a significantly lower odds of preemptive transplantation relative to private insurance holders (pre-KAS adjusted OR, [aOR] 0.26; [95% CI, 0.25 to 0.27], to 0.20 [95% CI, 0.18 to 0.22] post-KAS). Black and Hispanic patients experienced a similar phenomenon (aOR 0.48 [95% CI, 0.45 to 0.51] to 0.41 [95% CI, 0.37 to 0.45] and 0.43 [95% CI, 0.40 to 0.47] to 0.40 [95% CI, 0.36 to 0.46] respectively) compared with white patients.

CONCLUSIONS

Although the proportion of deceased donor kidney transplants performed preemptively increased slightly after KAS, disparities in preemptive kidney transplantation persisted after the 2014 KAS policy changes and were exacerbated for racial minorities and Medicare patients.