Pancreas Transplant as Treatment to Arrest Renal Function Decline in Patients With Type 1 Diabetes and Proteinuria

Recent findings from the Diabetes Control and Complications Trial and Epidemiology of Diabetes Interventions and Complications study showed that long-term improved glycemic control in patients with type 1 diabetes with normal renal function and normoalbuminuria can delay development of impaired renal function by at least 6.5 years, although the reduction in the relative risk of end-stage renal disease (ESRD) was not significant. The unanswered question is: can improvement of glycemic control delay the onset of ESRD in patients with established diabetic nephropathy? In this context, pancreas transplantation (PATx) can be considered the most effective intervention to restore normoglycemia. Can this aggressive/experimental intervention be applied to arrest/retard renal function decline? To answer this question, this review summarizes the relevant findings from observational studies conducted in cohorts of patients, followed up for 4 to 15 years, who underwent PATx. These noncontrolled studies provided positive answers to the earlier question, principally concerning a significant decrease in albumin excretion levels. However, current drugs used to prevent rejection could impair renal function, principally in recipients with low pretransplant estimated glomerular filtration rate (ie,60 mL/min). Unfortunately, all these studies had shortcuts that qualify interpretation of the findings. First, it is unclear how much initial estimated glomerular filtration rate loss results from nephrotoxic effect of antirejection drugs, and how much results from improved glycemia and its impact on the reduction of hyperfiltration. Second, the study designs did not consider the wide variation in rates of renal function loss observed in patients with established nephropathy (ie, one third are nonprogressors, one third are slow progressors, and one third are rapid progressors). Third, all studies were observational in nature and clinical trials are needed to properly evaluate the effectiveness of normalization of hyperglycemia through PATx on postponing the onset of ESRD in type 1 diabetes.