The reference value of anti-Müllerian hormone to diagnose polycystic ovary syndrome is inversely associated with BMI: a retrospective study

BACKGROUND: This study aimed to evaluate the cut-off value of anti-Müllerian hormone (AMH) combined with body mass index (BMI) in the diagnosis of polycystic ovary syndrome (PCOS) and polycystic ovary morphology (PCOM). METHODS: This retrospective study included 15,970 patients: 3775 women with PCOS, 2879 women with PCOM, and 9316 patients as controls. Multivariate logistic regression analysis was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for AMH. We randomly divided the patients into two data sets. In dataset 1, a receiver operating characteristic (ROC) curve was generated to analyze the accuracy of basic AMH levels in diagnosing PCOS and PCOM. The optimal cut-off value was calculated in dataset 1 and validated in dataset 2, expressed as sensitivity and specificity. RESULTS: In the PCOS group, obese patients had the lowest AMH levels, while underweight patients had the highest AMH level (P < 0.001). After adjusting for age, the ratio of luteinizing hormone (LH) and follicle stimulating hormone (FSH), serum testosterone level, and BMI, AMH was an independent predictor of PCOS and PCOM. In the group with BMI < 18.5 kg/m(2), the optimistic AMH cut-off value was 5.145 ng/mL with a sensitivity of 84.3% and specificity of 89.1%, whereas in the BMI ≥ 28 kg/m(2) group, the optimistic AMH cut-off value was 3.165 ng/mL with a sensitivity of 88.7% and specificity of 74.6%. For the BMI range categories of 18.5–24, 24.0–28 kg/m(2), the optimistic AMH cut-off values were 4.345 ng/mL and 4.115 ng/mL, respectively. The tendency that the group with lower weight corresponded to higher AMH cut-off values was also applicable to PCOM. In the same BMI category, patients with PCOM had a lower AMH diagnosis threshold than those with PCOS (< 18.5 kg/m(2), 5.145 vs. 4.3 ng/mL; 18.5–24 kg/m(2), 4.345 vs. 3.635 ng/mL; 24.0–28 kg/m(2), 4.115 vs. 3.73 ng/mL; ≥ 28 kg /m(2), 3.165 vs. 3.155 ng/mL). These cut-off values had a good diagnostic efficacy in the validation dataset. Based on different phenotypes and severity of ovulation disorders, the distribution of AMH in PCOS were also significantly different (P < 0.001). CONCLUSIONS: AMH is a potential diagnostic indicator of PCOS and is adversely associated with BMI. The AMH cut-off value for diagnosing PCOS was significantly higher than that for PCOM. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12958-023-01064-y.