Exponentially increased risk of infectious death in older renal transplant recipients

Background. The benefit of renal transplantation for patients with end-stage renal disease (ESRD) has been well documented. This benefit is seen throughout all age ranges of patients. However, it has been documented that older renal transplant recipients are at increased risk for death because of infectious causes when compared with younger recipients. The present study addresses whether this increased risk merely parallels an age-related increase in infectious mortality or is reflective of a particular vulnerability in older renal transplant recipients. Methods. Patients wait-listed and transplanted between 1988 and 1997 were analyzed utilizing the United States Renal Data System (USRDS) database. The primary study end point was patient death secondary to infection. Secondary end points included death secondary to cardiovascular cause and malignancy. Cox-proportional hazard models were utilized with all pertinent variables. Results. Death related to infectious cause increased exponentially in transplanted patients with increasing age (slope = 2.9(0.34x)), while it increased linearly (slope = 1.9x + 8.6) with increasing age for those patients on the waiting list. Overall mortality increases with age were equal between the wait-listed and transplanted groups. Conclusions. The overall survival benefit of transplantation is maintained in the older age groups. However, renal transplantation is associated with an increased risk for infectious death beyond the expected age-related increased risk in patients on the renal transplant waiting list. This may have an impact on future immunosuppressive regimens in this population.