Herbal medicine for Hashimoto's thyroiditis: A systematic review and network meta-analysis

Conventional treatments for Hashimoto's thyroiditis (HT) are limited. Herbal medicines (HM) are considered a potential intervention for the treatment of HT. This study aimed to investigate the efficacy and safety of HM for HT. A Bayesian network meta-analysis was conducted for patients with HT in randomized controlled trials identified in PubMed, Cochrane Library, Web of Science, EMBASE, Chinese Clinical Trial Registry (Chi CTR), China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (the VIP), China Chinese Biomedical Database (CBM), and Wanfang Database were searched from their inception to Oct 1, 2022. Outcomes included the primary outcome (TPOAb), secondary outcomes (TSH, TGAb, FT3, FT4, and traditional Chinese medicine symptom scores), and adverse events. This study was registered in PROSPERO (CRD42022363640). Sixteen trials were reviewed and 16 HM formulae were compared. Compared with non-drug therapy (NDT), all therapies, except for Tiaoqi-Qingjie Therapy, reduced the primary outcome of TPOAb with different levels of effectiveness, ranging from 0.01 (95%CI 0.00, 0.02) to 0.92 (95%CI 0.56, 1.53). Ranking probability analysis indicated that Yiqi Huayu Recipe, Liqi Xiaoying decoction, and Shugan Sanjie therapy reduced thyroid antibody levels the most, including TPOAb (100.0%, 90.9%, and 90.3%, respectively) and TGAb (98.3%, 94.4%, and 87.3%, respectively). All HMs displayed a significant effect on the TCM Symptom score and possibly benefitted the treatment of HT, ranging from 6.62 (95% CI 2.06, 21.24) to 94.50 (95% CI 15.97, 559.14). No serious adverse events were reported. Herbal medicines may be effective in the treatment of HT, especially in reducing thyroid antibody levels and improving clinical symptoms without affecting thyroid function. However, these results should be considered preliminary and further verified using high-quality evidence.