Impact of FAI on Metabolism and Adrenal Hyperandrogenism in Women with Polycystic Ovary Syndrome: a cross-sectional study

Background Although PCOS is a heterogeneous endocrinopathy in reproductive-aged women characterized by reproductive, endocrine, metabolic and psychological abnormalities, hyperandrogenism seems to be the most consistent feature. Therefore, the aim of the present study was to assess three hyperandrogenism parameters, FAI, TT and DHEAS, and their relationships with diverse metabolic indices, metabolic derangements and adrenal hyperandrogenism in women diagnosed with PCOS. Methods In this single-center cross-sectional study, 217 women aged 18–45 years with PCOS were enrolled. Baseline phenotypic, endocrine, and metabolic parameters, as well as multiple endocrine hormone levels, including insulin levels, thyroid function, sex hormones, ACTH, and cortisone levels, were collected. Dynamic function tests, such as OGTT, 1-mg dexamethasone suppression test, and ACTH stimulation test, were performed. Liver and vaginal ultrasound scans were also conducted to fully assess the metabolic and endocrine status of the participants. Results FAI was positively associated with BMI, waist circumference, hip circumference, waist-to-hip ratio, SBP, DBP, FPG, PPG, HbA1c, HOMA-IR, AUCGLU, AUCINS, TG, TC, LDL-C and UA (p < 0.05). Multivariate logistic regression revealed that FAI was an independent risk factor for multiple metabolic disorders, including overweight/obesity, fatty liver, dyslipidemia, insulin resistance, hyperglycemia, metabolic syndrome, and hyperuricemia. Moreover, the FAI was positively correlated with both TT and DHEAS ( p  < 0.05). In addition, the FAI was negatively related to basal, stimulated and suppressed cortisol and positively associated with ACTH, DHEAS and stimulated 17OHP in PCOS patients ( p  < 0.05). According to age range-based cutoff values of circulating DHEAS, 85 of 217 PCOS women with adrenal hyperandrogenism and higher levels of FAI likely experienced more severe adrenal hyperandrogenism. A ROC analysis was performed with the best cutoff point (FAI = 5.29, AUC = 0.724, 95% CI: 0.654–0.793, p  = 0.000, sensitivity = 71.8%, specificity = 64.2%). Conclusions The FAI is superior to TT and DHEAS in reflecting comprehensive features in terms of their correlation with phenotypic and metabolic parameters in patients with PCOS. Moreover, the FAI is also a promising biomarker for predicting adrenal hyperandrogenism, with the best cutoff point (value = 5.29). Trial Registration Chinese Clinical Trials Registry (registration number ChiCTR2000040904, date of registration 20201215).