Long-term renal allograft outcome after simultaneous kidney and pancreas transplantation.

BACKGROUND: In selected young patients with type 1 diabetes mellitus and end-stage renal failure, simultaneous pancreas and kidney (SPK) transplantation is the treatment of choice. We conducted a retrospective, case-controlled study to compare the function, survival and pathology of renal allografts after SPK and kidney-alone (KA) transplantations. METHODS: We studied 26 consecutive SPK patients and 67 KA controls matched for time of transplantation. Renal function was assessed by routine evaluation of serum creatinine and its course by the 1/serum creatinine vs time curve. Histologic evaluation of early biopsies (0-3 months post-transplantation, n=63), intermediate biopsies (3 months-1 year, n=75) and late biopsies (after 1 year, n=35) were performed by two independent reviewers. RESULTS: SPK and KA recipients differed significantly with regard to donor and recipient age, time on the waiting list, HLA sensitization, renal cold ischaemia time (CIT) and the incidence of delayed graft function. Acute rejection was more frequent after SPK than KA (54 vs 27%; P=0.01), despite higher trough levels of calcineurin inhibitors. After SPK and KA, actuarial patient and renal allograft survival and renal function were comparable at 1 and 4 years. Severe chronic lesions, especially vascular lesions, and calcineurin-inhibitor nephrotoxicity were more frequent in intermediate and late biopsies in the SPK group. CONCLUSIONS: We confirmed that patient and graft survival is comparable between SPK and KA recipients. Despite the use of optimal organs and shorter CIT in SPK, renal graft function was not different in the two groups. Histologic chronic lesions were more severe in SPK than in KA recipients. This might be caused by acute rejection episodes or be due to more severe nephrotoxicity after SPK, because of higher doses of calcineurin inhibitors, or higher sensitivity to calcineurin-inhibitor nephrotoxicity.