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

BACKGROUND: Hemolytic uremic syndrome (HUS) accounts for <1% of renal transplants in the US. There are limited data on the characteristics and outcomes of HUS in pediatric and adult kidney transplant recipients in the US. METHODS: This study included all renal transplant recipients identified with HUS (N=1,233) as a cause of end-stage renal disease between 1987 and 2013 using the UNOS/OPTN database. The cohort was divided into two age groups: pediatric (N=447) and adult (N=786). Main outcomes were acute rejection rate at one-year, allograft and patient survival, and recurrence of HUS post-transplant. Both age groups were then compared with a propensity score (1:2 ratio) matched control group with an alternative primary kidney disease (non-HUS cohort: pediatric [N= 829] and adult [N=1,547]). RESULTS: In pediatric cohort, when compared to 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. HUS was associated with allograft loss (HR=1.40, 95%CI 1.14-1.71) in adult recipients. Patients with HUS recurrence had significantly lower allograft and patient survival rates compared to the non-recurrent group in both age groups. Acute rejection was one of the major predictor of HUS recurrence in adults (OR=2.64, 95%CI 1.25-5.60). Calcineurin inhibitors (CNI) were not associated HUS recurrence in both age groups. CONCLUSION: Pediatric HUS-patients, unlike adult recipients, have similar outcomes compared to the PS matched controls. Recurrence of HUS is associated with poor allograft and patient survival in pediatric and adult patients. Use of CNIs seem to be safe as a part of maintenance immunosuppression post-transplantation. A comprehensive national registry is urgently needed.