The effect of metformin on homocysteine levels in patients with polycystic ovary syndrome: A systematic review and meta‐analysis

Purpose Metformin is widely used as an insulin sensitizer in polycystic ovary syndrome (PCOS) patients. However, previous studies have found that the effect of metformin on the level of homocysteine were not consistent in PCOS patients. The aim of this review was to analyze the effect of metformin on homocysteine levels in patients with PCOS patients. Methods The Cochrane Library, Pubmed, and Web of Science were searched according to predefined search terms. There is no restriction for publication time and language. Results Eleven studies were included and the data were extracted. The homocysteine level in PCOS patients was significantly increased after taking metformin (mean difference [MD] −1.33; 95% confidence interval [CI] −2.16 to −0.49, p = 0.002). Subgroup analysis showed that the level of homocysteine was generally increased in PCOS patients with body mass index (BMI) ≥25 after taking metformin alone (MD −1.82; 95% CI −2.56 to −1.07, p