Efficacy and safety of Danggui Liuhuang Decoction combined with antithyroid drugs for hyperthyroidism: A systematic review and meta-analysis

Ethnopharmacological relevance: Hyperthyroidism is a prevalent clinical endocrine disorder. Danggui Liuhuang Decoction (DGLHD), a traditional Chinese herbal medicine formula, has shown potential benefits for patients with hyperthyroidism in recent studies. However, the clinical efficacy and safety of DGLHD have not been systematically evaluated. To address this, a systematic review and meta-analysis are necessary to comprehensively evaluate its efficacy and safety in treating hyperthyroidism.

Aim of the study: To evaluate the efficacy and safety of DGLHD in treating hyperthyroidism.

Materials and methods: A comprehensive search of eight databases was conducted from their inception to November 2023 to identify randomized controlled trials (RCTs) comparing DGLHD combined with antithyroid drugs (ATDs) to ATDs alone. The quality of the included studies was assessed using the Cochrane Risk of Bias Assessment Tool. A meta-analysis was conducted using Revman 5.3 software, while publication bias was evaluated with Stata 16.0 software. The certainty of the evidence was assessed using the GRADE system.

Results: Overall, 20 RCTs involving 1,757 patients with hyperthyroidism were included in this analysis. The methodological quality was generally low. The meta-analysis revealed that, compared to ATDs alone, the combination of DGLHD with ATDs was more effective in reducing free triiodothyronine (FT3) [standardized mean difference (SMD) = -0.80, 95% confidence interval (CI): -1.31 to -0.28, P = 0.002], free thyroxine (FT4) [SMD = -1.47, 95% CI: -1.99 to -0.94, P < 0.00001], Traditional Chinese Medicine (TCM) syndrome scores [mean difference (MD) = -3.65, 95% CI: -4.68 to -2.62, P < 0.00001], and adverse events [relative risk (RR) = 0.23, 95% CI: 0.15 to 0.36, P < 0.00001]. Additionally, combining DGLHD with ATDs led to an improvement in thyroid-stimulating hormone (TSH) levels [SMD = 2.75, 95% CI: 1.37 to 4.13, P < 0.0001] and increased the effectiveness rate of TCM syndrome [RR = 1.20, 95% CI: 1.08 to 1.34, P = 0.001]. However, other outcomes, such as recurrence rates and quality of life scores, could not be analyzed through meta-analysis owing to the limited number of included studies.

Conclusion: Combining DGLHD with ATDs may alleviate clinical symptoms, enhance thyroid function, and reduce adverse events in patients with hyperthyroidism. Moreover, this treatment appears to be safe for clinical use. However, owing to the limited quantity and quality of the included studies, these conclusions require further validation through more large-sample, multicenter, high-quality RCTs.