As presented in Table 3, the combined use of metformin and simvastatin are more beneficial to reduce the T level (SMD –0.64, 95% CI –1.13 to –0.15) than metformin alone treatment in PCOS patients (P = .012), and there was no significant difference in the LH (SMD –0.58, 95%CI –1.66 to –0.50), FSH (SMD 0.41, 95% CI –0.78–1.59), prolactin (SMD –1.38, 95% CI –2.93–0.17) between experimental and control groups (all P > 0.05). This evidence concerns the gene BRD2 and polycystic ovary syndrome.