Screening for insulin resistance in women with polycystic ovarian syndrome

INTRODUCTION: Insulin resistance is implicated in the pathogenesis of polycystic ovarian syndrome (PCOS). Insulin-sensitizing agents are increasingly used in the treatment of infertility and hirsutism in PCOS. However, not all women with PCOS are insulin-resistant. OBJECTIVE: To assess the degree of insulin resistance within a clinic population of women referred for treatment of oligomenorrhoea or infertility. DESIGN: We evaluated 25 consecutive PCOS outpatients referred for treatment of menstrual dysfunction/infertility and a matched control group. All underwent a standard oral glucose tolerance test (OGTT) with serial insulin measurements. Insulin sensitivity was calculated using homeostasis model assessment (HOMA). RESULTS: Five of the 25 clinic patients had abnormal glucose handling (two had previously unknown type 2 diabetes and three had impaired glucose tolerance). Fasting and 2-h insulin levels were significantly higher in the PCOS women. Mean HOMA-S (insulin sensitivity) was even lower for PCOS women with normal GTT status (mean (95% confidence interval): 0.53 (0.34-0.72)) than for controls (0.94 (0.84-1.04)) (F = 4.2, p < 0.001). HOMA-B (pancreatic beta-cell function) was nearly tripled for normal GTT status PCOS women at 273 (205-342) versus 105 (70-139) for controls (F = 6.8, p < 0.001). CONCLUSIONS: The results suggest a role for routine measurement of HOMA-S in identifying women with PCOS with insulin resistance with a view to targeting them with insulin-sensitizing agents.