An analysis of predictors of long‐term cadaveric renal allograft survival

To determine factors predictive of long‐term graft function in patients treated prophylactically with an antilymphocyte antibody, 670 first cadaveric adult renal transplant procedures performed between 1985 and 1991 were reviewed. The actuarial 1‐ and 5‐year patient survival in this group was 95% and 87% respectively, and graft survival was 84% and 70% respectively. The final analysis was based on a study group of 635 patients which excluded 28 patients who lost grafts to early technical failures and 8 patients who were not induced with an antilymphocyte preparation. Multivariate analysis showed that 5‐year graft survival was lower in patients with delayed graft function (p=0.0001), in those who had an acute rejection episode in the first 6 months post‐transplant (p=0.0001), in rccipients greater than 55 years of age at the time of transplant (p=0.0001), in patients who were highly sensitized at the time of transplant (p=0.0331) and, finally, in those who received a graft from an older donor (p=0.044). The 209 patients with delayed graft function had a 16% lower long‐term graft survival than 425 patients with early graft function (62% vs. 78% respectively at 5 years). One or more rejection episodes in the first 6 months post‐transplant (329 patients) reduced long‐term graft survival by 13% compared to those who did not have a rejection episode (67% vs. 80% respectively at 5 years). 219 patients who were free of early rejection episodes and had early graft function had a 5‐year graft survival of 85% compared to 60% in the 122 patients who had early rejection and delayed graft function (p<0.0005). Recipient age of over 55 years reduced graft survival at 5 years because of death with a functioning graft. The other two independent variables, degree of sensitization and donor age, had a weaker effect on graft survival by increasing the risk ratio to 1.013 for sensitization and to 1.104 for donor age. There was only a minor interaction between time to graft function and rejection activity. 52% of the 219 patients were free of rejection episodes whereas only 42% of the 209 patients with delayed function had no rejection (p<0.05). HLA matching did not have an independent effect on long‐term graft outcome, but did interact with rejection in that of 57% of patients with 2 or fewer BDR mismatches were free of rejection as compared to 44% of patients who had more than 2 mismatches free of rejection (p<0.0001). Serum creatinine at 6 months was a dependent variable that influenced longterm survival. Patients with a serum creatinine at 6 months of ≤200 μmol/ 1 (2.27 mg%) had a 27% increase in long‐term survival compared to those with more impaired function (86% vs. 59% actuarial survival at 5 years. post‐transplant) (p<0.0005).