Effect of waiting time on renal transplant outcome

Background Numerous factors are known to impact on patient survival after r enal transplantation. Recent studies have confirmed a survival advantage fo r renal transplant patients over those waiting on dialysis. We aimed to inv estigate the hypothesis that longer waiting times are more deleterious than shorter waiting times, that is, to detect a "dose effect" for waiting time . Methods. We analyzed 73,103 primary adult renal transplants registered at t he United States Renal Data System Registry from 1988 to 1997 for the prima ry endpoints of death with functioning graft and death-censored graft failu re by Cox proportional hazard models. All models were corrected for donor a nd recipient demographics and other factors known to affect outcome after k idney transplantation. Results. A longer waiting time on dialysis is a significant risk factor for death-censored graft survival and patient death with functioning graft aft er renal transplantation (P < 0.001 each). Relative to preemptive transplan ts, waiting times of 6 to 12 months, 12 to 24 months, 24 to 36, 36 to 48, a nd over 48 months confer a 21, 28, 41, 53, and 72% increase in mortality ri sk after transplantation, respectively. Relative to preemptive transplants, waiting times of 0 to 6 months, 6 to 12 months, 12 to 24 months, and over 24 months confer a 17, 37, 55, and 68% increase in risk for death-censored graft loss after transplantation, respectively. Conclusions. Longer waiting times on dialysis negatively impact on post-tra nsplant graft and patient survival. These data strongly support the hypothe sis that patients who reach endstage renal disease should receive a renal t ransplant as early as possible in order to enhance their chances of long-te rm survival.