TNF and polycystic ovary syndrome: In the subgroup analysis, significant difference in the TNF-α levels of PCOS patients versus the controls were observed in the subgroup with HOMA-IR ratio >1.72(SMD = 0.967, 95% CI = 0.103–1.831, P = 0.028, I2 = 93.5%)(S5 Fig, Table 2).