Mortality among younger and older recipients of kidney transplants from expanded criteria donors compared with standard criteria donors

Abstract

Background and objectives The quality and age of donor organs are known to have a major effect on patient and graft outcomes, but it is uncertain whether this association is uniform for all recipients. We aimed to determine whether the use of expanded criteria deceased donor (ECD) kidneys for transplantation compared with standard criteria deceased donor (SCD) kidneys has a different association with survival in younger (age<60 years old) compared with older (age ±60 years old) recipients. Design, setting, participants, & measurements Using data from the Australian and New Zealand Dialysis and Transplant Registry (1997-2009), we compared the risk of all-cause mortality and death with functioning graft among younger and older recipients who had received either an SCD or an ECD kidney using the adjusted Cox proportional hazard models. Results In total, 3822 patients were transplanted between 1997 and 2009. Over a follow-up period of 21,249 person-years (a median duration of 5.3 years [interquartile range, 2.22-8.6 years]), 567 recipients (n=385 for those age<60 years old; n=182 for those age ±60 years old) died. Recipient age was an effect modifier between donor types, all-cause mortality, and death with functioning graft (P values for interaction were 0.05 and 0.04, respectively). In younger recipients, there was an excess risk of all-cause mortality (adjusted hazard ratio [HR], 1.55; 95% confidence interval [95% CI], 1.23 to 1.97) and death with functioning graft (adjusted HR, 1.72; 95% CI, 1.28 to 2.29) after transplantation with ECD kidneys compared with SCD kidneys, but there was no statistically significant association among older recipients (adjusted HR, 1.11; 95% CI, 0.80 to 1.54 and ad- justed HR, 1.30; 95% CI, 0.89 to 1.89, respectively). This excess risk was largely caused by death from car- diovascular disease. Conclusions There was an excess risk of all-cause mortality and death with functioning graft when younger recipients were transplanted with ECD kidneys compared with SCD kidneys. These findings suggest that caution is needed in allocating ECD kidneys to younger recipients.