Hurry Up and Wait: Modeling Kidney Transplant Wait Times under Wait-List Expansion Scenarios

Background: Kidney transplantation offers survival benefits and superior quality of life compared with maintenance dialysis for patients with end-stage kidney disease (ESKD). While over 500,000 Americans currently receive dialysis, deceased donor transplantation is limited to approximately 20,000 patients annually. Expanding access to kidney transplant is a top priority of public policy. Strategies involve adding more patients to the waitlist and increasing organ supply. However, the effect of these interventions on transplant wait times has not been explored. Methods: We constructed a decision analytic Markov model to simulate a cohort of approximately 660,000 patients with chronic kidney disease (CKD) and estimated glomerular filtration rate (eGFR) <20ml/min and ESKD on dialysis over a ten-year period. We then used Kaplan-Meier survival analysis to estimate median wait time by counting time on the waitlist until transplantation, censoring for waitlist removal and death. We compared current wait times (status quo) to three strategies: 1) waitlist expansion by 10%, 2) waitlist expansion by 50%, and 3) waitlist expansion by 50% combined with a 50% reduction in the kidney nonuse rate. Results: Under the status quo, median wait time was 48.2 months (4.01 years). Under the 10% expansion strategy, wait times increased to 53.1 months (4.43 years; + 5.0 additional months). Under the 50% expansion strategy, median wait times increased substantially to 74.2 months (6.2 years; + 26.1 additional months). 50% waitlist expansion combined with 50% reduction in the kidney nonuse rate attenuated the increase in wait times to 67.5 months (5.6 years; + 19.4 additional months) and resulted in 2,252 additional kidney transplants. Conclusion: Alternate strategies prolonged the median time to kidney transplant by 5 to 26 additional months depending on the degree of expansion and presence of additional organ supply. Efforts to expand access to transplantation without concomitant increases in organ supply would likely result in longer wait times. Systems-level efforts to increase organ supply and enhance allocation efficiency should be prioritized in conjunction with measures which substantially add to the transplant waitlist. Funding: NIDDK Support, Private Foundation Support