Insulin Resistance is the Predominant Pathophysiologic Feature of Hyperglycemia in Newly Diagnosed Overweight and Obese Type 2 Diabetes Mellitus in Two University Hospitals in Malaysia

Abstract

Objectives. To examine the profile of insulin resistance and secretory dysfunction and their relationship with clinical/metabolic parameters among patients with newly diagnosed type 2 diabetes mellitus in Malaysia. Methods. A cross-sectional study of 161 newly diagnosed type 2 diabetic subjects was performed. Fasting blood samples were collected for glucose, insulin and biochemistry. Demographic and anthropometric data were recorded. Homeostatic model assessment (HOMA) was used to estimate insulin resistance (IR) and beta-cell function. Control subjects consist of 45 individuals with normal glucose tolerance. Results. Our type 2 diabetic subjects had significantly higher HOMA-IR and lower HOMA-%B versus controls (6.4 ± 5.3 vs. 2.5 ± 1.5, p < 0.0001 and 93.5 ± 87.8% vs. 201.0 ± 118.0%, p < 0.0001). Elevated body mass index or waist circumference, hypertension and hypertriglyceridaemia were independent predictors for insulin resistance. Low body mass index or waist circumference, hypertriglyceridaemia and increasing age were independent predictors for beta cell dysfunction. Conclusions. Contrary to a predominantly insulin secretory dysfunction reported by other studies from Asia, our study of largely overweight and obese type 2 diabetic subjects showed a predominance of insulin resistance over secretory dysfunction. Obesity, hypertension and hypertriglyceridaemia were predictive of insulin resistance while being lean with hypertriglyceridaemia and increasing age were predictive of beta cell dysfunction.