Agreement among insulin sensitivity indexes on the diagnosis of insulin resistance in polycystic ovary syndrome and ovulatory women.

Objective: The objective was to compare agreement on the diagnosis of insulin resistance (IR) among insulin sensitivity indexes in both ovulatory women and those with polycystic ovary syndrome (PCOS).

Study Design: In an observational study, the 75-g oral glucose tolerance test was performed in 105 women with PCOS and 51 ovulatory women. The insulin sensitivity indexes used were insulin quantitative sensitivity check index (QUICKI), 1/homeostasis model assessment-insulin resistance (1/HOMA-IR), area under curve for insulin (AUC-I), and the Matsuda insulin sensitivity index (COMP). For the IR diagnosis we used cut-off values described in recent publications (insulin >12 microIU/ml, 1/HOMA-IR <0.47, QUICKI < or =0.333, AUC-I > or =7000 microIU/ml 120 min, and COMP <4.75.

Results: Excellent agreement was assessed among insulin, QUICKI, and 1/HOMA-IR. However, the rate of IR detected by these indexes in the PCOS group (44.8-51.4%) was lower than expected. New cut-offs were then determined based on COMP results. Using these values, 1/HOMA-IR and QUICKI showed excellent agreement (kappa=0.83) with COMP.

Conclusion: The observed agreements among insulin, QUICKI and 1/HOMA-IR were higher than 93%. Therefore, clinicians may choose any of those obtaining similar results. For clinicians who prefer COMP, but are looking for a simpler test to detect IR in PCOS women, the use of QUICKI and 1/HOMA-IR with the new cut-offs seems reasonable.