Delayed graft function, acute rejection, and outcome after cadaver renal transplantation: A multivariate analysis

The impact of delayed graft function on outcome after cadaver renal transplantation has been controversial, but most authors fail to control their analyses for the presence or absence of rejection. We studied 457 adult recipients of primary cadaver allografts at a single institution during the cyclosporine era. All patients received sequential immunosuppression. The incidence of delayed graft function (defined as dialysis being required during the first week after transplant) was 23%. There was a significant association between delayed graft function and cold ischemia time >24 hr (P=0.0001) and between delayed graft function and the occurrence of at least one biopsy-proven rejection episode (P=0.004). Actuarial graft survival was not significantly different when comparing delayed graft function versus no delayed graft function for patients without rejection (P=0.2). However, it was significantly worse for patients with both delayed graft function and rejection versus those with delayed graft function but no rejection (P=0.005), as well as for grafts preserved >24 hr versus ≤24 hr (P=0.007). By multivariate analysis, delayed graft function per se was not a significant risk factor for decreased graft survival for patients without rejection (P=0.42). In contrast, rejection significantly decreased graft survival for grafts with immediate function (relative risk = 2.3, P=0.0002), particularly in combination with delayed graft function (relative risk = 4.2, P<0.0001). While cold ischemia time >24 hr was also a significant risk factor (relative risk = 1.9, P=0.02), other variables (preservation mode, 0 HLA Ag mismatch, age at transplantation, gender, diabetic status, and panel-rcactive antibody at transplantation) had no impact on graft survival. Patient survival was significantly affected by the combination of delayed graft function and rejection (relative risk = 3.1, P< 0.0001), age at transplantation > 50 years (relative risk = 2.6, P<0.0001), and diabetes (relative risk = 1.8, P=0.006). Further studies are necessary to elucidate the mechanisms linking delayed graft function and rejection, which, in combination, lead to poor allograft outcome.