Waiting Time for Second Kidney Transplantation and Mortality

Background and objectives The median kidney transplant half-life is 10-15 years. Because of the scarcity of donor organs and immunologic sensitization of candidates for retransplantation, there is a need for quantitative information on if and when a second transplantation is no longer associated with a lower risk of mortality compared with waitlisted patients treated by dialysis. Therefore, we investigated the association of time on waiting list with patient survival in patients who received a second transplantation versus remaining on the waiting list. Design, setting, participants, & measurements In this retrospective study using target trial emulation, we analyzed data of 2346 patients from the Austrian Dialysis and Transplant Registry and Eurotransplant with a failed first graft, aged over 18 years, and waitlisted for a second kidney transplantation in Austria during the years 1980-2019. The differences in restricted mean survival time and hazard ratios for all-cause mortality comparing the treatment strategies retransplant versus remain waitlisted with maintenance dialysis are reported for different waiting times after first graft loss. Results Second kidney transplantation showed a longer restricted mean survival time at 10 years of follow-up compared with remaining on the waiting list (5.8 life months gained; 95% confidence interval, 0.9 to 11.1). This survival difference was diminished in patients with longer waiting time after loss of the first allograft; restricted mean survival time differences at 10 years were 8.0 (95% confidence interval, 1.9 to 14.0) and 0.1 life months gained (95%confidence interval,214.3 to 15.2) for patients with waiting time for retransplantation of < 1 and 8 years, respectively. Conclusions Second kidney transplant is associated with patient survival compared with remaining waitlisted and treatment by dialysis, but the survival difference diminishes with longer waiting time.

Automated summary

The study results indicate that second kidney transplantation is associated with longer survival time compared to remaining on the waiting list after 10 years of follow-up. However, this survival difference diminishes with longer waiting times after the loss of the first graft.