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 < 0.00 1). 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.