How much insulin resistance in polycystic ovary syndrome? Comparison of HOMA-IR and insulin resistance (Belfiore) index models.

Abstract

IntroductionPolycystic ovary syndrome (PCOS), the commonest endocrinopathy of women in reproductive age, is often accompanied by insulin resistance (IR), hirsutism and/or fertility problems. The aim of the study was to assess the prevalence of IR in women diagnosed with PCOS.Material and methodsThe study involved 137 women diagnosed with PCOS, according to the Rotterdam consensus criteria (2003). Insulin resistance was assessed according to the HOMA-IR method and insulin resistance (Belfiore) index (IRI) derived from glucose and insulin during the oral glucose tolerance test.ResultsThere was a significant (p < 0.0001) but relatively moderate correlation between IRI and HOMA-IR (r = 0.5 and r = 0.57 for a linear and non-linear model, respectively). Insulin resistance was more prevalent according to IRI (49.6%) than according to HOMA-IR (22.6% and 15.8% for 3.46 and 3.8 cut-off points, respectively, p < 0.01). The majority of patients with high HOMA-IR also had high IRI (e.g. 86%, for HOMA > 3.8), but the majority of patients with raised IRI would not be diagnosed as insulin resistant according to HOMA (61.7% and 73.5%, for HOMA-IR3.46 and HOMA-IR3.80, respectively).ConclusionsThe insulin resistance (Belfiore) index indicates more cases of insulin resistance than HOMA-IR in women with PCOS. Therefore, detection of insulin resistance among women with PCOS is highly method-dependent with more severe cases being detected with HOMA-IR than with IRI.