MANAGEMENT OF ENDOCRINE DISEASE: The impact of subclinical hypothyroidism on anthropometric characteristics, lipid, glucose and hormonal profile of PCOS patients: a systematic review and meta-analysis

Objective Subclinical hypothyroidism (SCH) is encountered in 10–25% of women with PCOS. To date, it remains unclear whether this coexistence influences the severity of metabolic and hormonal profile of these patients. The purpose of our systematic review is to investigate this potential relation. Methods We systematically searched Medline, Scopus, ClinicalTrials.gov, Cochrane Central Register of Controlled Trials (CENTRAL) and Google Scholar databases together with reference lists from included studies. All prospective and retrospective observational cohort studies that investigated the impact of subclinical hypothyroidism on hormonal and metabolic parameters of PCOS patients were included. The methodological quality of studies was assessed with the Ottawa–Newcastle criteria. Statistical meta-analysis was performed with the RevMan 5.3 software. Results Twelve studies were finally included in the present review, which enrolled 2341 PCOS patients. Among them, 577 had subclinical hypothyroidism, whereas the remaining 2077 were PCOS women with normal thyroid function. The presence of SCH significantly affected HDL (MD –3.92 mg/dL 95% CI: –6.56, –1.29) and triglycerides levels (26.91 mg/dL 95% CI: –3.79, 50.02). HOMA-IR was also affected (MD 0.82 95% CI: 0.15, 1.50). On the other hand, LDL, fasting glucose and 2-h OGTT were not influenced. Similarly, prolactin, FSH, LH, LH/FSH ratio and sex hormone-binding globulin remained unaffected. Conclusion Subclinical hypothyroidism does not influence the hormonal profile of women with PCOS. On the other hand, it results in mild metabolic abnormalities, which are not clinically important in a short-term setting.