Abstract

BACKGROUND
Insulin resistance is prevalent in women with polycystic ovary syndrome (PCOS), and it makes them to have high risk for development of type 2 diabetes. Evaluation of insulin sensitivity would be important to predict their risks. Although the euglycemic-hyperinsulinemic clamp technique is the gold standard for measuring insulin sensitivity, it is too hard to practice in large epidemiologic studies. The aim of this study is to verify the validity of various insulin sensitivity indexes from oral glucose tolerance test (OGTT) in women with PCOS. METHODS: We performed euglycemic-hyperinsulinemic clamp (target glucose; 90 mg/dL, insulin ;~1 mU/kg.min) to obtain insulin-mediated glucose disposal rate (M-value) in 62 non-diabetic women with PCOS (BMI < 23 kg/m2; n = 37, BMI > or = 23 kg/m2; n = 25). Homeostasis model assessment [HOMA(IR)], quantitative insulin sensitivity check index (QUICKI), glucose to insulin ratio (G/I ratio), whole body insulin sensitivity index [ISI(COMP)], metabolic clearance rate of glucose [MCR(est)-OGTT(1,2)], and insulin sensitivity indexes [ISI(est)-OGTT(1,2)] were calculated from plasma glucose and insulin levels from standard 75-g OGTT. The correlations of various insulin sensitivity indexes from OGTT with M-value were evaluated. RESULTS: In lean women with PCOS (BMI < 23 kg/m2, n = 37), ISI(COMP) (r = 0.36, P < 0.05), MCRest-OGTT1 (r = 0.49, P < 0.01), ISI(est)-OGTT(1) (r = 0.50, P < 0.01), MCR(est)-OGTT(2) (r = 0.45, P < 0.01) and ISI(est)-OGTT(2) (r = 0.40, P < 0.05) were significantly correlated with M-value. In overweight and obese women with PCOS (BMI > or = 23 kg/m2, n = 25), HOMA(IR) (r = -0.40, P < 0.05), QUICKI (r = 0.40, P < 0.05), MCR(est)-OGTT(1) (r = 0.76, P < 0.001), ISI(est)-OGTT(1) (r = 0.63, P < 0.001), MCR(est)-OGTT(2) (r = 0.58, P < 0.01) and ISI(est)-OGTT(2) (r = 0.42, P < 0.05) showed significant correlations with M-value. CONCLUSION: MCR(est)-OGTT(1) and ISI(est)-OGTT(1) were the most reliable and easily accessible insulin sensitivity indexes obtained from OGTT for measuring of insulin sensitivity in women with PCOS regardless of obesity.

• Keywords: Euglycemic hyperinsulinemic clamp;Insulin sensitivity indexes;Oral glucose tolerance test;Polycystic ovary syndrome;