Metabolic syndrome in drug-naive Chinese patients with insulin-sensitive and insulin-resistant type 2 diabetes

BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by impaired insulin sensitivity (Si) and insulin secretion. Previous studies may have underestimated differences in the incidence of risk factors in insulin-sensitive diabetes mellitus (IS-DM) and insultin-resistant diabetes mellitus (IR-DM) patients and have not been conducted in the Chinese population. OBJECTIVES: We explored differences in metabolic risk factors between Chinese patients with newly diagnosed, insulin-resistant (IR) and insulin-sensitive (IS) T2DM. DESIGN: Cross-sectional study. SETTING: Cardinal Tien Hospital, Taiwan in 2011. METHODS: All participants received a frequently sampled intravenous glucose tolerance test. The acute insulin response after a glucose load (AIRg), Si, disposition index (DI), and glucose effectiveness (GE) were determined. Using the median Si value from 90 people without diabetes as a cutoff (1.19x10(-4) mU/L/min), patients were divided into two groups, IS-DM and IR-DM. Multivariate regression analysis was used to examine the independent influence of MetS components on Si and AIRg. MAIN OUTCOME MEASURE(S): Insulin sensitivity. RESULTS: We enrolled 122 participants. In addition to higher probabilities of having MetS, IR-DM patients had a significantly higher body mass index (BMI), AIRg, and GE but a lower DI than IS-DM patients. Si correlated with BMI and triglycerides, and AIRg correlated with BMI and high-density lipoprotein cholesterol. BMI was the only component related to Si in the multivariate analysis. Furthermore, the AIRg was associated with BMI and fasting plasma glucose. Because BMI was the most critical factor, a cutoff value (25.0 kg/m(2)) was obtained from the receiver operating characteristic curve for predicting IR-DM. It showed a sensitivity and specificity of 60.8% and 60.9%, respectively. CONCLUSIONS: IR-DM patients had more MetS components than IS-DM patients. In Chinese patients obesity is the most critical factor for discriminating IR-DM from IS-DM. Patients with a BMI higher than 25 kg/m(2) were prone to develop IR-DM. LIMITATIONS: The size of our study cohort was relatively small, which may weaken the statistical power of the study.