Validation of Simple Indices to Assess Insulin Sensitivity and Pancreatic Beta-Cell Function in Patients with Renal Dysfunction

Abstract

Background/Aims: Insulin resistance and hyperinsulinemia has been reported in patients with chronic renal failure. However, usefulness and validation of new indices for assessment to insulin sensitivity and pancreatic beta-cell function were unknown. Methods: We evaluated insulin sensitivity and pancreatic beta-cell function in 61 normal glucose tolerant (NGT) and 60 diabetic (DM) subjects; both groups were subdivided as normal renal function (NRF; C_cr ≥ 70 ml/min) and impaired renal function (IRF; C_cr <70 ml/min). Insulin sensitivity were assessed by homeostasis model assessment of insulin resistance (HOMA-IR) and plasma glucose and insulin concentrations obtained at fasting or during a 75-gram oral glucose tolerance test (insulin sensitivity index), and pancreatic beta-cell function were assessed by insulinogenic index, first-phase insulin secretion index, and area under the response curve for plasma insulin (insulin-AUC_0–180). Results: There was no evidence of insulin resistance in NGT-IRF group. No differences in both insulinogenic index and first-phase insulin secretion index between NGT-NRF and NGT-IRF, but these were significantly decreased in DM-NRF and DM-IRF. There were inverse linear correlations between the insulin sensitivity index and insulin-AUC_0–180 in patients with NGT and DM, respectively. These correlations were similarly robust in NRF subjects and IRF subjects. Conclusions: New indices for assessment of insulin sensitivity and pancreatic beta-cell function calculated from plasma glucose and plasma insulin concentrations after OGTT are applicable for clinical use even in patients with renal dysfunction.