Optimal androgen concentration cut-off values for identifying abnormal insulin sensitivity in Korean women with polycystic ovary syndrome

Objective: This study evaluated the relationship between serum androgen concentrations and validated insulin sensitivity indices in Korean women with polycystic ovary syndrome (PCOS) and established optimal androgen thresholds for identifying abnormal insulin sensitivity. Methods: A total of 180 Korean females aged 18-35 years with newly diagnosed PCOS were enrolled. Fasting-state insulin sensitivity assessment indices (ISAIs) were calculated, and participants with abnormal levels according to at least one established ISAI criterion were classified as having abnormal insulin sensitivity. Spearman's correlation analysis assessed relationships between insulin sensitivity parameters and four androgens: total testosterone (TT), free testosterone (FT), dehydroepiandrosterone sulfate (DHEA-S), and 17α-hydroxyprogesterone (17-OHP). Receiver operating characteristic (ROC) curve analysis was used to define the most accurate androgen cutoff values for predicting abnormal insulin sensitivity. Results: Among the four androgens tested, TT, FT, and DHEA-S showed significant associations with most insulin resistance (IR) parameters, whereas 17-OHP showed no significant correlation. In the ROC curve analysis, only FT achieved moderately accurate predictive performance (area under the curve [AUC], 0.759), while TT, DHEA-S, and 17-OHP showed AUC values indicating less accurate predictions. The optimal FT cutoff to detect abnormal insulin sensitivity was 1.325 pg/mL (sensitivity, 77.8%; specificity, 64.0%). Conclusion: FT showed the strongest association with parameters related to insulin sensitivity and could serve as a complementary opportunistic indicator of IR in PCOS. Women with PCOS who had serum FT levels ≥1.325 pg/mL were identified as having abnormal insulin sensitivity.