Risks and benefits of preemptive second kidney transplantation.

BACKGROUND Information to guide the timing of a second kidney transplantation is limited. METHODS We compared outcomes of 3509 preemptive and 14,075 nonpreemptive second kidney transplant recipients in the U.S. Renal Data System between 1995 and 2007. RESULTS Preemptive recipients had less acute rejection (12% vs. 16%; P<0.0001) and delayed graft function (8% vs. 23%; P<0.0001). Preemptive transplantation was associated with a lower multivariate adjusted risk of allograft failure from any cause including death (hazard ratio [HR], 0.88; 95% confidence interval [95% CI], 0.81-0.96) and death with a functioning graft (HR [95% CI], 0.76 [0.66-0.87]) but a similar risk of death-censored graft loss (HR [95% CI], 0.98 [0.88-1.08]). The benefits of preemptive transplantation were evident in all patients groups with first transplant survival equal to or more than 1 year; however, a 34% increased risk of death-censored graft loss was observed in preemptive recipients when first transplant survival was less than 1 year. CONCLUSIONS Benefits and risks of preemptive transplantation vary between primary and second transplant recipients. Benefits in second transplant recipients are primarily due to decreased death with a functioning graft, with no difference in death-censored graft survival. Preemptive transplantation was beneficial when first transplant survival was equal to or more than 1 year but associated with increased risk when graft survival was less than 1 year.