Objective: To evaluate the impact of obesity and various phenotypes of polycystic ovary syndrome (PCOS) on the insulin sensitivity index (ISI) and insulin resistance (IR).
Methods: ISI and IR from 273 women in four phenotypes of PCOS and control groups were evaluated retrospectively.
Results: The ISI and the percentage of IR were not significantly different among discrete phenotypes of PCOS groups and normal controls. Obesity (OR = 14.0, 95% CI (Confidence Interval), 7.5-26.5) results in a higher risk for developing insulin resistance than hyperandrogenemia (OR = 2.1, 1.3-3.6), oligomenorrhea (OR = 1.8, 1.0-3.3) and polycystic ovary morphology (PCOM) (OR = 1.4, 0.8-2.7).
Conclusion: The ISI did not differ significantly among the various phenotypes of PCOS. In comparison with hyperandrogenemia, chronic anovulation, and PCOM, obesity was the dominant risk factor in determining insulin resistance in women with PCOS.