Deceased donor kidney transplantation (DDKT) confers a greater survival benefit to adult waitlist candidates on dialysis than those managed preemptively, investigators reported at the 2022 American Transplant Congress (ATC 2022) in Boston, Massachusetts.
The current US Kidney Allocation System (KAS) allows for DDKT candidates not yet on dialysis to accrue waiting time points by listing at a transplant center with a low estimated glomerular filtration rate.
“By assigning waiting time points to patients not yet on dialysis, KAS ignores the Final Rule requirements to rank-order candidates by medical urgency and exacerbates disparities in kidney transplantation,” William F. Parker, MD, PhD, from the University of Chicago in Illinois stated on behalf of his team. “To improve efficiency and equity, KAS should be revised to eliminate pre-dialysis waiting time points.” His team’s position agrees with a recommendation from the National Academies of Sciences, Engineering, and Medicine to eliminate predialysis waiting time points. Dr Parker noted that in other Western countries outside the US, a patient must be on dialysis to join the waitlist with minor exceptions.
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Among 132,909 adult candidates (mean age 52 at listing; 60% male) on the 2005-2010 waitlist, 64,589 patients (48.6 %) received a kidney transplant. DDKT increased 5-year absolute patient survival from 50.8% to 82.4%.
The survival benefit of DDKT was greater for patients receiving than not receiving dialysis at each year of wait time, regardless of diabetes status, Dr Parker reported. The investigators adjusted the model for transplant center effect, ischemic time, donor Kidney Disease Profile Index (KDPI), recipient age, and history of previous transplant or diabetes.
Dr Parker’s team compared outcomes for 2 similar recipients at the median age of 55 years without diabetes who had a KDPI of 43% and 5 years of accrued wait time. In these recipients, a preemptive kidney transplant would increase survival from 73% to 93%, whereas a kidney transplant after dialysis would improve survival from 31% to 78% — an absolute 5-year survival advantage of 19% vs 47%.
“Transplanting patients on dialysis saves more lives in the short-term than doing preemptive transplants,” Dr Parker said in an interview with Renal & Urology News. He acknowledge that over the long term, patients on dialysis have higher rates of graft failure and lower survival.
The Organ Procurement and Transplantation Network (OPTN) considers all patients able to receive hemodialysis as equivalently urgent, but Dr Parker disagrees. “The current OPTN policy ignores the fact that candidates on dialysis have a much higher risk of death without transplant than candidates not yet on dialysis,” he said.
Dr Parker also noted that large racial and socioeconomic disparities exist in preemptive transplants. “Socially advantaged patients get access to the waiting list earlier and start accumulating waiting time points before the initiation of hemodialysis,” he said. “It’s simply not fair for these patients to be getting preemptive transplants when most recipients have to wait for years on dialysis.”
References
Parker WF, Becker Y, Gibbons R. The association of pre-transplant dialysis time and the survival benefit of deceased donor kidney transplantation [abstract]. Am J Transplant. 2022;22 (suppl 3). Presented at: ATC 2022 meeting; June 4-8; Boston, Massachusetts. Abstract 310.
New report recommends changes to U.S. organ transplant system to improve fairness and equity, reduce nonuse of donated organs, and improve the system’s overall performance [news release]. National Academies of Sciences, Engineering, and Medicine; February 25, 2022.
