Homeostatic Model Assessment for Insulin Resistance (HOMA-IR): A Better Marker for Evaluating Insulin Resistance Than Fasting Insulin in Women with Polycystic Ovarian Syndrome

Objective: To assess the utility of HOMA-IR in assessing insulin resistance in patients with polycystic ovary syndrome (PCOS) and compare it with fasting insulin for assessing insulin resistance (IR). Study Design: Observational study. Place and Duration of Study: Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi, from January 2009 to September 2012. Methodology: Medical chart review of all women diagnosed with PCOS was performed. Of the 400 PCOS women reviewed, 91 met the inclusion criteria. Insulin resistance was assessed by calculating HOMA-IR using the formula (fasting glucose x fasting insulin)/405, taking normal value <2 in adults and hyperinsulinemia based on fasting insulin levels >= 12 mu IU/ml. Results: A total of 91 premenopausal women diagnosed with PCOS were included. Mean age was 30 +/- 5.5 years. Mean HOMA-IR of women was 3.1 +/- 1.7, respectively with IR in 69% (n= 63) women, while hyperinsulinemia was present in 60% (n= 55) women (fasting Insulin 18.5 +/- 5.8 mu IU/ml). Hyperandrogenism was present in 53.8% (n= 49), whereas 38.5% (n= 35) women had primary infertility or subfertility, while 65.9% (n= 60) had menstrual irregularities; and higher frequencies were observed in women with IR. Eight subjects with IR and endocrine abnormalities were missed by fasting insulin. Conclusion: Insulin resistance is common in PCOS and it is likely a pathogenic factor for development of PCOS. HOMA-IR model performed better than hyperinsulinemia alone for diagnosing IR.