Role of Supplementation with Selenium and Myo-Inositol Versus Selenium Alone in Patients of Autoimmune Thyroiditis: A Systematic Review and Meta-Analysis.

Objective: The main objective was to assess the therapeutic efficacy of selenium alone versus a combination of myo-inositol and selenium (MI + Se) in treating patients with autoimmune thyroiditis (AIT). The study aims to determine which treatment option is more effective in restoring euthyroid state, as indicated by changes in thyroid-stimulating hormone (TSH), T3, T4, thyroid peroxidase antibodies (TPOAb), and thyroglobulin antibodies (TgAb).

Methods: Google Scholar and PubMed databases were searched for randomized controlled trials (RCTs) and observational studies that reported outcomes of combined treatment (MI + Se) in restoring a euthyroid state, specifically comparing it with selenium-only (Se-only) treatment. Changes in TSH, T3, T4, TPOAb, and TgAb levels from baseline were defined as indicators to compare the effect of combined versus selenium-only treatment in restoring euthyroid levels. The Cochrane risk of bias tool and Newcastle Ottawa Scale were used to assess the quality of the randomized control trials included in the study. Review Manager (version 5.4, Nordic Cochrane Centre, Copenhagen, Denmark) was used for statistical analysis.

Result: We pooled three studies, enrolling 151 participants in the MI + Se group and 137 participants in the Se group. Supplementation of Se with MI demonstrated a significant reduction in TSH levels compared to Se alone (SMD = -1.15, 95% CI: -1.60 to -0.69,  < .00001). MI + Se treatment also significantly reduced TgAb levels compared to Se (SMD = -0.51, 95% CI: -0.78 to -0.24,  = .0002). In contrast, TPOAB, T3 and T4 levels were non-significantly reduced from baseline in patients treated with MI + Se when compared to Se alone (SMD = -0.81, 95% CI: -0.44 to 0.09,  = .20), (SMD = 0.16, 95% CI: -0.09 to 0.42,  = .22), and (SMD = 0.30, 95% CI: -0.23 to 0.83,  = .26) respectively.

Conclusion: Supplementation of Se with MI showed a significant reduction in TSH and TgAb levels compared to selenium-only treatment, with a non-significant reduction in TPOAB, T3, and T4 levels. This entails the need for powered clinical trials and observational studies with longer follow-ups to critically assess the role of combined therapy in restoring euthyroid state in patients with AIT.