Cold Ischemia Time, Kidney Donor Profile Index, and Kidney Transplant Outcomes: A Cohort Study.

Rationale & Objective: An average of 3,280 recovered deceased donor kidneys are discarded annually in the United States. Increased cold ischemia time is associated with an increased rate of organ decline and subsequent discard. Here we examined the effect of prolonged cold ischemia time on kidney transplant outcomes. Study Design: Retrospective observational study. Setting & Participants: Recipients of deceased donor kidney transplants in the United States from 2000 to 2018. Exposure: Recipients of deceased donor kidneys were divided based on documented cold ischemia time: ≤16, 16-24, 24-32, 32-40, and >40 hours. Outcomes: The incidence of delayed graft function, primary nonfunction, and 10-year death-censored graft survival. Analytical Approach: The Kaplan-Meier method was used to generate survival curves, and the log rank test was used to compare graft survival. Results: The rate of observed delayed graft function increased with cold ischemia time (20.9%, 28.1%, 32.4%, 37.5%, and 35.8%). Primary nonfunction also showed a similar increase with cold ischemia time (0.6%, 0.9%, 1.3%, 2.1%, and 2.3%), During a median follow-up time of 4.6 years, 37,301 recipients experienced death-censored graft failure. Analysis based on kidney donor profile index (KDPI) demonstrated significant differences in 10-year death-censored graft survival, with a death-censored graft survival in recipients of a kidney with a KDPI <85% of 71.0% (95% CI, 70.5%-71.5%), 70.5% (95% CI, 69.9%-71.0%), 69.6% (95% CI, 68.7%-70.4%), 65.5% (95% CI, 63.7%-67.3%), and 67.2% (95% CI, 64.6%-69.6%), compared to 53.5% (95% CI, 51.1%-55.8%), 50.7% (95% CI, 48.3%-53.1%), 50.3% (95% CI, 46.6%-53.8%), 50.7% (95% CI, 45.1%-56.1%), and 48.3% (95% CI, 40.0%-56.1%), for recipients of a kidney with a KDPI >85%. Limitations: Heterogeneity of acceptance patterns among transplant centers, presence of confounding variables leading to acceptance of kidneys with prolonged cold ischemia times. Conclusions: Cold ischemia time was associated with an increased risk of delayed graft function and primary nonfunction. However, the effect of increased cold ischemia time is modest and has less impact than the KDPI. Transplant programs should not consider prolonged cold ischemia time alone as a predominant reason to decline an organ, especially with a KDPI <85%.

Kidney utilization and outcomes of liver transplant recipients who were listed for kidney after liver transplant after the implementation of safety net policy.

In 2017, United Network for Organ Sharing (UNOS) established the safety net policy with set criteria for offering kidney transplantation (KT) for patients who developed end-stage renal disease between 60 and 365 days after liver transplant (LT). We provide an update on the impact of the policy. We analyzed UNOS data of liver recipients transplanted between 1987 and 2020 who developed acute kidney injury requiring dialysis within 60 days before or after LT and subsequently listed for KT. We identified 407 patients who were listed for kidney after LT before policy and 248 patients after policy. Median waiting time to KT was shorter after policy (324 days vs. 2827 days). There was a higher proportion of candidates who were listed for subsequent KT within 1-year after policy (94.8% vs. 63.6%). KT rate was also higher after policy (87.7 vs. 30.7 per 100 patient-years at risk). Most importantly, we started to observe a net negative kidney utilization in end-stage liver disease setting (i.e., summation of simultaneous liver kidney and kidney after liver transplant in the first-year after LT has decreased from 1086 to 876 transplants in 2019). Such findings are consistent with a more efficient system and more appropriate allocation of organs.

Outcomes of small pediatric donor kidney transplants according to donor weight.

A small pediatric deceased donor (SPD) weight cutoff whether to transplant as en bloc (EB) or single pediatric (SP) kidney is uncertain. Using UNOS/OPTN data (2000-2019), 27 875 SPDs were divided by (i) EB (11.4%) or SP (88.6%) and (ii) donor weight [≤10 (5.4%), >10-15 (8.3%), >15-18 (3.7%), >18-20 (2.9%), and >20 kg (79.7%)]. SP >20 kg and adult deceased donors (grouped by Kidney Donor Profile Index, KDPI, <30, 30-85, and >85) were used as references. The primary outcome was 10-year graft failure. In SP <10 kg, the hazard ratio (HR) for overall graft failure was 1.64 (1.38-2.20) compared with EB <10 kg, and 1.45 (1.18-1.80) compared with SP >20 kg. In SP >10-15 kg, HR was 1.31 (1.12-1.54) compared with EB >10-15 kg, and 1.04 (0.91-1.18) compared with SP >20 kg. In SP >15 kg, the risk was the same as SP >20 kg. Ten-year overall graft survival of SP 12 kg was comparable to SP >20 kg (62% vs. 57%). Ten-year death censored graft failure of SP >10-15 kg (70%) and SP >15-18 kg (70%) was like the adult donors with KDPI 30-85 (67%). In conclusion, we recommend single kidney transplants from SPDs with weight >12 kg to adult recipients in centers with experience in SPD transplants to optimize organ utilization.

Association between ethnicity and kidney transplant waitlist outcomes beyond estimated post-transplant survival score.

White kidney transplant candidates have the highest pre-transplant mortality rate compared to other ethnicities. The reason for a higher mortality rate is not well-understood. Estimated post-transplant survival (EPTS) score has been used to predict patient survival after transplant and may be associated with pre-transplant survival. First-time kidney transplant candidates listed between 2015 and 2018 were identified from the Organ Procurement Transplantation Network database. Individuals listed for multiple organs, at multiple centers, and age <18 years were excluded. We examined the impact of ethnicity on waitlist mortality and delisting. A total of 114 806 candidates were included. The study population was categorized into four groups which were 43% white, 28% Black, 19.2% Hispanic, and 9.8% "other ethnicities." At 5.2 years, the cumulative incidences of death and delist were 32%, 31%, 29%, and 26%, respectively. Compared to whites, adjusted subdistribution hazard ratio (aSHR) for death and delist among Black, Hispanics, and "other ethnicities" were 0.92 (95% CI 0.89-0.95), 0.89 (95% CI 0.85-0.91), and 0.76 (95% CI 0.72-0.80) after adjustment by EPTS along with other factors, respectively. After adjusting for EPTS score along with additional confounding factors and functional status at initial listing, white ethnicity was independently associated with an increased risk for death and delist.

Impact of donor obesity on allograft outcomes after kidney transplantation adjusted for kidney donor profile index - a national cohort study.

Obesity in deceased kidney donors is a known risk factor for poor allograft outcomes. The Kidney Donor Profile Index (KDPI) has been introduced to predict graft survival in deceased donor kidney transplantation (DDKT). Obesity, however, is not included in KDPI. We study the impact of donor obesity on DDKT outcomes after adjusting for organ quality by KDPI. The Organ Procurement Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) data of DDKT from 2005 to 2017, with donor BMI ≥ 18.5 kg/m2 and weight >80 kg were included. There was a total of 66 382 DDKTs with 10 917 death-censored graft failures. For KDPI ≤ 30%, the 10-year death-censored graft survival (DCGS) rates among donor BMI < 30, 30-35, 35-40, 40-45 and ≥45 kg/m2 groups were 75.9%, 75.4%, 76.1%, 74.9% and 79.6%, respectively. For KDPI > 30%, 10-year DCGS rates were 67.5%, 66.1%, 65.9%, 62.6% and 63.2%, respectively. After adjusting for known confounding factors including KDPI, donor obesity was not independently associated with an increased risk for graft failure. In DDKT with donor weight >80 kg, donor obesity was not associated with a lower long term DCGS compared to non-obesity when KDPI ≤ 30%.

Time to second kidney transplantation in young adults after failed pediatric kidney transplant.

BACKGROUND: Under the current kidney allocation system, pediatric candidates listed prior to age 18 receive priority for high-quality deceased donor organs. This has resulted in a decline in living donor transplantation in pediatrics, despite superior outcomes of living donor transplantation. Due to a young age at transplantation, most pediatric kidney transplant recipients require re-transplantation. The effects of a previously failed deceased donor vs a previously failed living donor on re-transplant candidates are unknown. METHODS: Using the United Network for Organ Sharing database, we examined 2772 re-transplant recipients aged 18-30 years at time of relisting for second KT from 2000 to 2018 with history of prior pediatric KT (age ≤ 18 years). RESULTS: PFLDKT recipients compared to those with PFDDKT had shorter median waiting times and dialysis time regardless of their second donor type (14.0 vs 20.3 months, and 19.1 vs 34.5 months, respectively). PFLDKT recipients had higher re-transplant rates (adjusted HR 1.17, 95% CI 1.09-1.27, and adjusted HR 1.05, 95% CI 0.95-1.15 when calculating from time of relisting and time of returning to dialysis, respectively). PFDDKT recipients were more likely to have higher median PRA levels (90% vs 73%). CONCLUSIONS: Re-transplant candidates who received a previous deceased donor as a child had a higher level of sensitization, longer waiting time, and dialysis exposure compared to those with PFLDKT. Among primary pediatric kidney transplant candidates, consideration should be considered for living donor transplantation, despite the priority for deceased donor organs, to avoid increased sensitization and longer waiting times for with re-transplantation.

Evaluation of Renal Disease in Patients With Cirrhosis.

Renal dysfunction in cirrhosis is common and is associated with increased mortality. Identifying and treating reversible causes of renal disease can significantly improve outcomes. The etiology, approach, and evaluation of renal disease in this group of patients is similar to the noncirrhosis patient, with a few specific caveats. Renal disease may be unrelated to the cause of cirrhosis (eg, prerenal acute kidney injury, acute tubular necrosis), occur as a manifestation of the same systemic disease responsible for the liver disease (eg, chronic viral hepatitis B and C infection) or as a consequence of cirrhosis (hepatorenal syndrome). Kidney impairment may be underrecognized in patients with cirrhosis due to over-reliance on creatinine-based glomerular filtration rate equations used in clinical practice. The first steps of evaluation for the renal disease include a thorough medical history to identify the underlying cause of cirrhosis and any potential trigger for renal dysfunction, physical examination, and review of prior laboratory records for baseline renal function. Renal imaging and urinalysis should be performed on all cirrhotic patients with renal dysfunction to establish the presence of urinary obstruction, chronicity and intrinsic renal disease.