Postoperative oral glucose tolerance and stimulated insulin secretion: A predictor of endocrine graft function more than 10 years after pancreas-kidney transplantation

Background. After pancreas transplantation, endocrine function is determined by the insulin secretory capacity of the transplanted pancreas. The authors evaluated the predictive value of postoperative oral glucose tolerance test (OGTT) and stimulated insulin secretion on long-term endocrine function. Methods. Forty-one patients after pancreas-kidney transplantation with systemic venous drainage were studied. Patients were categorized to have normal glucose tolerance (NGT) or impaired glucose tolerance (IGT) (World Health Organization criteria: NGT, <7.8 mM; IGT, 7.8-11.1 mM 120 min after glucose intake) and high or low total insulin secretion. Mean follow-up of graft function and patient outcome was 10.2+/-0.5 years after OGTT. Results. Patients with IGT had grafts with a longer ischemia time and a significantly worst urine amylase excretion as compared with patients with NGT. Using Kaplan-Meier survival analysis, patients with NGT had better long-term pancreatic function as compared with IGT in the follow-up after performing the first OGTT (mean, 10.9+/-0.2 vs. 8.8+/-0.9 years of graft function; P=0.02), but there was no difference in patient survival and kidney graft function. Also, high insulin secretion predicted significantly longer pancreas graft function as compared with low insulin secretion (P=0.04). Conclusions. Although IGT does not lead to poorer long-term patient survival and kidney graft function, it does predict compromised long-term endocrine function of the transplanted pancreas. Therefore, postoperative OGTT are useful tools for identification of patients at risk of, long-term endocrine graft failure after pancreas transplantation.