Assessing the Limits in Kidney Transplantation: Use of Extremely Elderly Donors and Outcomes in Elderly Recipients

Background. Patient survival with end-stage renal disease is longer after kidney transplantation (KT) compared with those remaining on dialysis. Nevertheless, this remains uncertain when receiving a kidney from a donor >= 80 years old. Methods. In a longitudinal mortality study in the Catalan Renal Registry including 2585 patients >= 60 years old on dialysis and placed on the KT waiting list, 1084 received a first KT from a deceased donor aged 60 to 79 years and 128 from a deceased donor >= 80 years. We calculated adjusted risk of graft loss by means of competing-risks regression, considering patient death with functioning graft as a competing event. To assess patient survival benefit from KT, we calculated the adjusted risk of death by nonproportional hazard analysis, taking the fact of being transplanted as a time-dependent effect. Considering all KT >= 60 (n = 1212), we assessed whether the benefit of KT varied per different recipient characteristics by calculating the interaction effect between all potential mortality risk factors and the treatment group. Results. Compared with kidneys from donors 60 to 79 years old, graft survival was significantly lower for kidneys from donors aged >= 80 years (subhazard ratio = 1.55; 95% confidence interval, 1.00-2.38; P = 0.048). In comparison with those who remained on dialysis, adjusted risk of death 12 months after transplantation in recipients with a kidney from donors >= 80 years was 0.54 (95% confidence interval, 0.38-0.77; P < 0.0001). Conclusions. Despite KT from octogenarian deceased donors being associated with reduced graft survival, recipients had lower mortality rates than those remaining on dialysis, even if the kidney came from an extremely aged donor.