Surrogate index for insulin sensitivity composed of factors not using glucose and insulin in Japanese patients with diabetes

Abstract

Introduction: The aim of the present study is to propose a novel index of insulin sensitivity instead of homeostasis model assessment of insulin resistance (HOMA-IR), which has a fundamental limitation of validity when applied to subjects with lower insulin secretions or high fasting plasma glucose (FPG) levels. Materials and Methods: A total of 25 apparently healthy subjects and 24 patients with type 2 diabetes participated in the study. We assessed relationships of glucose infusion rate (GIR), obtained by using the euglycemic hyperinsulinemic glucose clamp technique, with other measurements of metabolic and anthropometric parameters. Results: In multiple regression analysis, a model including log-transformed (log) triglyceride/log high-density lipoprotein cholesterol and waist circumference as predictive variables showed the strongest contribution rate to explain GIR as an outcome variable (R2 = 0.710). The validity of estimated GIR (EGIR) calculated from the regression equation composed of these factors was further tested in another group of patients including type 1, type 2 and pancreatic diabetes in whom HOMA-IR could not be used as a result of either high FPG or low fasting insulin level, or both. Even in those patients, EGIR showed a good positive relationship with measured GIR (r = 0.681, P < 0.0001). Conclusions: The proposed index without HOMA-IR can adequately show insulin sensitivity in Japanese diabetic patients, even in cases with the limitation of HOMA-IR application. © 2010 Asian Association for the Study of Diabetes and Blackwell Publishing Asia Pty Ltd.