Donor age and delayed graft function as predictors of renal allograft survival in rejection-free patients

Transplant recipients of kidneys harvested from old donors have a high incidence of delayed graft function (DGF) and a poor graft outcome. This result is partly explained by the increased incidence of acute rejection in patients suffering from DGF. However, the long-term impact of donor age and DGF in rejection free renal transplants is not well established. The aim of the present work is to evaluate the impact of donor age and DGF on long-term outcome in renal transplants with or without acute rejection. We review all cadaveric kidney transplants performed in our centre between April 1984 and December 1995 treated with a cyclosporin-based immunosuppression. Five hundred and ninety-five patients were included. The overall incidence of DGF was 29.1%, and this event was associated with an increased donor age and cold ischaemia time. Univariate and multivariate analysis showed that graft loss was associated with acute rejection (relative risk (RR) 2.24, 95% confidence interval (CI) 1.62-3.01); DGF (RR 1.83, 95% CI 1.32-2.54); donors >50 years (RR 1.65, 95% CI 1.13-2.38); and retransplantation (RR 1.52, 95% CI 1.01-2.31). In rejection-free patients there were two independent predictors of graft failure: donor >50 years (RR 2.40, 95% CI 1.45-4.01); and DGF (RR 2.42, 95% CI 1.53-3.84). Regardless of the presence of acute rejection, delayed graft function amplifies the detrimental effect of advanced donor age on long-term graft outcome.