O: BJECTIVES: Copeptin has been reported to play an important role in metabolic response in women with PCOS. However, the optimal cut-off value for detecting subjects with insulin resistance (IR) remains undetermined. We investigated whether copeptin can serve as an indicator of IR and tried to determine the optimal cut-off value of plasma copeptin concentration in detecting subjects with PCOS and IR.
Material and methods: We carried out a case-control study on 158 women with PCOS and HOMA-IR < 2.5, 96 women with PCOS with HOMA-IR ≥ 2.5, and 70 healthy volunteers. Plasma copeptin, as well as hormonal, biochemical, metabolic, and IR parameters, were measured. To investigate whether copeptin allows IR to be predicted in PCOS, we used logistic regression models and ROC curve analysis.
Results: Median plasma copeptin concentration was the highest in the women with PCOS and HOMA-IR ≥ 2.5. Logistic regression analysis revealed that copeptin was the strongest predictor of HOMA ≥ 2.5 (OR: 53.34 CI 7.94-358.23, p < 0.01). Analysis of ROC curves indicated that the cut-off value above 4 pmol/L of plasma copeptin concentration had high (99%) specificity but very low (21%) sensitivity in diagnosing of IR (AUC 0.607 (95% CI 0.53-0.68.
Conclusions: Our findings suggest that copeptin is associated with IR in PCOS patients, but due to low sensitivity should not be considered as a marker of IR.
Keywords: AVP; PCOS; copeptin; insulin resistance; metabolic syndrome.