The crosstalk between polycystic ovary syndrome and Hashimoto thyroiditis: a systematic review and meta-analysis.

Polycystic ovary syndrome (PCOS) and Hashimoto thyroiditis (HT) are endocrine disorders; when they co-exist, they exacerbate each other's serious consequences. Literature is scarce on these important diseases. This meta-analysis aimed to assess the prevalence of HT in both patients with PCOS and control subjects, as well as insulin resistance (IR) and lipid profile in patients with PCOS with and without HT. We systematically searched PubMed, Embase, Web of Science, and Google Scholar from inception to February 2026 using combinations of keywords and MeSH terms related to polycystic ovary syndrome, Hashimoto thyroiditis, autoimmune thyroid disease, insulin resistance, and metabolic outcomes. We retrieved 209 articles, of which 38 full texts were screened, and 22 studies were included in the meta-analysis. HT was higher in patients with PCOS compared to control subjects (OR = 2.69, 95% CI: 1.63 to 4.42), and women with PCOS and HT exhibited higher HOMA-IR than women with PCOS alone (MD = -0.92, 95% CI: -1.50 to -0.35). However, the TC, LDL, HDL, and TG were similar in patients with PCOS with and without HT (MD = -0.61, 95% CI: -1.40 to 0.18; MD = -0.49, 95% CI: -1.69 to 0.72; MD = 0.01, 95% CI: -0.09 to 0.07; and MD = -0.06, 95% CI: -0.35 to 0.23, respectively). HT was more prevalent among women with PCOS than in controls. Women with PCOS and concomitant HT had higher IR than women with PCOS alone. However, the TC, LDL, HDL, and TG were similar in patients with PCOS with and without HT. Prospective studies with long follow-up are needed.