Five-year graft and patient outcomes after preemptive versus non-preemptive living donor kidney transplantation: a single-center retrospective cohort study

Abstract Background The clinical benefit of preemptive kidney transplantation over transplantation following dialysis initiation remains controversial, particularly in recipients of living donor grafts. We aimed to compare five-year clinical outcomes between preemptive and non-preemptive living donor kidney transplantation, with additional adjustment for dialysis duration and immunologic compatibility. Methods In this single-center retrospective cohort study, 175 adult recipients of living donor kidney transplantation between 2013 and 2020 were included (preemptive, n = 69; non-preemptive, n = 106). The primary endpoints were five-year graft loss and all-cause mortality. Secondary outcomes included biopsy-proven acute rejection and BK virus infection. Survival analyses were performed using the Kaplan–Meier method and Cox proportional hazards models. Multivariable models were constructed with parsimonious adjustment for recipient age, donor age, and HLA mismatch count. Separate models were used to evaluate the effects of preemptive transplantation and dialysis duration. Results Baseline demographic and clinical characteristics were comparable between groups, except for dialysis duration (0 [0–0] vs. 10 [2–48] months). During five-year follow-up, rates of acute rejection (15.9% vs. 13.2%, p = 0.662), BK virus infection (24.6% vs. 23.6%, p = 1.000), graft loss (5.8% vs. 6.6%, p = 1.000), and mortality (8.7% vs. 5.7%, p = 0.544) did not differ significantly between the preemptive and non-preemptive groups. Kaplan–Meier analyses showed no significant differences in graft survival (log-rank p = 0.824) or patient survival (log-rank p = 0.434). In multivariable Cox models, preemptive transplantation was not independently associated with graft loss (HR 0.88; 95% CI 0.26–3.03; p = 0.842) or mortality (HR 1.85; 95% CI 0.58–5.96; p = 0.302). Similarly, dialysis duration was not significantly associated with graft loss or mortality. In exploratory analyses, increasing recipient age was associated with higher mortality risk, while HLA mismatch count showed an association with mortality; however, these findings should be interpreted cautiously given the limited number of events. Conclusions In this cohort of living donor kidney transplant recipients, preemptive transplantation was not independently associated with improved five-year graft or patient survival after adjustment for selected clinical and immunologic variables. These findings suggest that, in well-selected living donor populations, long-term outcomes may be more strongly influenced by donor and recipient characteristics than by the timing of transplantation. The low number of outcome events limits statistical power, and modest differences between groups cannot be excluded.