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Prediction of age at menopause in women with polycystic ovary syndrome: methodological issues

I was interested to read the paper by Minooee and colleagues published in Climacteric in February 2018. Considering the role of anti-M€ ullerian hormone (AMH) in female fertility and its high levels in women with polycystic ovary syndrome (PCOS), the longer reproductive span of these women is in doubt. The authors aimed to improve earlier predictions to substantiate the question as to whether women with PCOS reach menopause later. The study included 378 PCOS cases and 784 eumenorrheic non-hirsute women. Based on their results, the serum concentration of AMH among PCOS participants was significantly higher than in the controls (5.4 vs. 1.4 ng/ml, p< 0.001). The estimated mean ages at menopause were 51.4 years and 49.7 years in PCOS cases and healthy controls, respectively. The authors concluded that, as reflected through significantly higher average levels of AMH in PCOS women, their predicted reproductive lifespan could be 2 years longer than their normoovulatory counterparts. However, these results are not the most appropriate estimates for prediction. First, correlation even if statistically significant does not guarantee prediction of an outcome. Moreover, for prediction studies, we need data from two different cohorts, or at least from one cohort divided into two, first to develop a prediction model and subsequently to validate it. Misleading results are generally the main outcome of research that fails to validate its prediction models. Finally, in prediction studies, we must assess the interactions between important variables. Final results can be impacted dramatically when qualitative interactions are present. This means that most of the time, without assessing the interaction terms, prediction studies will mainly produce misleading messages. Conflict of interest No potential conflict of interest was reported by the author.