Comparison of preemptive living-donor kidney transplantation with incident hemodialysis in Japan: a region-specific analysis from a setting with limited deceased-donor kidney transplantation

BACKGROUND: In Japan, deceased-donor kidney transplantation is rare, and a substantial proportion of patients who would be placed on a transplant waiting list in Western countries remain within the dialysis population. This study was designed to examine the survival difference between preemptive transplantation and dialysis using an incident hemodialysis cohort, comparable to recipients of preemptive living-donor kidney transplantation. METHODS: This retrospective study used a province-wide cohort including 1257 incident hemodialysis patients from a multicenter database and 244 recipients of preemptive living-donor kidney transplantation from a transplant center in Aichi Prefecture, Japan. Propensity score matching was performed using demographics, comorbidities, functional status, body mass index, laboratory values, and cardiac function. The primary outcome was patient survival, assessed using restricted mean survival time, defined as the mean survival time to a pre-specified time point, calculated by numerical integration. RESULTS: After matching, 234 incident hemodialysis patients and 78 preemptive living-donor kidney transplant recipients were analyzed, with a median follow-up of 1494 days. No patients in the hemodialysis cohort underwent kidney transplantation during the follow-up period. Preemptive living-donor kidney transplantation was associated with longer survival, with an additional 155 days of restricted mean survival time over 1825 days, and a significantly lower mortality risk. The benefit was mainly driven by reduced cardiovascular mortality, which was more pronounced in older patients and those with preexisting cardiovascular disease. CONCLUSIONS: Preemptive living-donor kidney transplantation as initial kidney replacement therapy was associated with superior survival compared with incident hemodialysis, particularly in older individuals and those with preexisting cardiovascular disease.