Temporal Trend and Time-Varying Effect of Preemptive Second Kidney Transplantation on Graft Survival: A 30-Year Single-Center Cohort Study

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, -14.3 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.

Preemptive second kidney transplantation is associated with better graft survival compared with non-preemptive second transplantation: a multicenter French 2000-2014 cohort study

The impact of preemptive second kidney transplantation (2KT) on graft and patient survival is poorly established. The association between preemptive 2KT (p2KT, N = 93) and outcomes was estimated in a multicenter French cohort of 2KT (N = 1314) recipients using propensity score methods. During the follow-up, there were 274 returns to dialysis and 134 deaths. p2KT was associated with lower death-censored graft loss (HR = 0.39 [0.18-0.88], P = 0.024) and graft failure from any cause including death (HR = 0.42 [0.22-0.80], P = 0.008). Similar associations were observed for death with a functioning graft, although not reaching statistical significance (HR = 0.47 [0.17-1.26], P = 0.13). There was a significant interaction between donor type and p2KT (P for interaction = 0.016). Indeed, p2KT was not significantly associated with the risk of graft failure from any cause including death in living donor 2KT (P = 0.39), whereas the association was substantial in the deceased donor subset (HR = 0.30 [0.14-0.64], P = 0.002). Of note, the adjusted graft survival of p2KT with deceased donor paralleled that of 2KT with living donor, either preemptive or not (93.8% vs. 88.6% at 4 years and 76.1% vs. 70.5% at 8 years, P = 0.13). This large French multicenter study analyzed using propensity scores suggests that p2KT is associated with better graft prognosis.