Earlier is not necessarily better in preemptive kidney transplantation

While preemptive (before chronic dialysis) transplantation is associated with improved graft survival, it is unclear whether higher versus lower pretransplant kidney function is associated with even better graft survival after preemptive transplantation. We examined 671 first, preemptive, kidney-only transplantations at Hennepin County Medical Center and the University of Minnesota Medical Center 1984-2006. We estimated pretransplant glomerular filtration rate (eGFR, mL/min/1.73 m²) using the Modification of Diet in Renal Disease (MDRD) equation with Group 1: <10.0 (7.3 ± 1.7, N = 324), Group 2: 10.0-14.9 (12.0 ± 1.4, N = 217) and Group 3: ≥15.0 (21.1 ± 10.0, N = 130). The mean difference in eGFR for Group 1 versus 3 was 13.8 pretransplant, 16.3 on day 1 and 13.9 on day 2 posttransplant. By week 1 and year 1 posttransplant, the differences between Groups 1 and 3 reduced to 6.3 and 4.5 mL/min/1.73 m², respectively. The adjusted relative risk (RR; Cox analysis) for graft failure was not significantly lower with higher pretransplant eGFR (reference eGFR <10.0); RR = 0.99 (95% confidence interval = 0.68-1.44, p = 0.9432) for eGFR 10.0-14.9; RR = 1.35 (0.89-2.05, p = 0.1588) for eGFR ≥15. Thus, early preemptive transplantation with higher eGFR does not necessarily improve graft survival after kidney transplantation, compared to preemptive transplantation with lower pretransplant eGFR.