Characteristics and Outcomes of Renal Transplant Recipients with Hemolytic Uremic Syndrome in the United States

Background. Hemolytic uremic syndrome (HUS) accounts for less than 1% of renal transplants in the United States. There are limited data on the characteristics and outcomes of HUS in pediatric and adult kidney transplant recipients in the United States. Methods. This study included all renal transplant recipients identified with HUS (N = 1233) as a cause of end-stage renal disease between 1987 and 2013 using the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. The cohort was divided into 2 age groups: pediatric (N = 447) and adult (N = 786). Main outcomes were acute rejection rate at 1 year, allograft and patient survival, and recurrence of HUS posttransplant. Both age groups were then compared with a propensity score (PS) (1:2 ratio) matched control group with an alternative primary kidney disease (non-HUS cohort: pediatric [N = 829] and adult [N = 1547]). Results. In pediatric cohort, when compared with the PS-matched controls, acute rejection, death censored allograft, and patient survival was similar in the HUS group. However, in the adult cohort, the graft and patient survivals were significantly worse in the HUS group. The HUS was associated with allograft loss (hazard ratio, 1.40, 95% confidence interval, 1.14-1.71) in adult recipients. Patients with HUS recurrence had significantly lower allograft and patient survival rates compared with the nonrecurrent group in both age groups. Acute rejection was one of the major predictor of HUS recurrence in adults (odds ratio, 2.64; 95% confidence interval, 1.25-5.60). Calcineurin inhibitors were not associated HUS recurrence in both age groups. Conclusions. Pediatric HUS patients, unlike adult recipients, have similar outcomes compared with the PS-matched controls. Recurrence of HUS is associated with poor allograft and patient survivals in pediatric and adult patients. Use of calcineurin inhibitors seem to be safe as a part of maintenance immunosuppression posttransplantation. A comprehensive national registry is urgently needed.