Tripterygium wilfordii Hook F versus conventional synthetic disease-modifying anti-rheumatic drugs as monotherapy for rheumatoid arthritis: a systematic review and network meta-analysis

Background: Tripterygium wilfordii Hook F (TwHF), a medicinal plant that has been widely used in Chinese traditional medicine, is proven effective for treating rheumatoid arthritis (RA), but its clinical efficacy and safety remain largely undefined in comparison with conventional synthetic disease modifying anti-rheumatic drugs (DMARDs). Methods: PubMed, Embase, Cochrane Library, CNKI, VIP, CBM, and WanFang Databases. Endpoints were ACR 20, 50, and 70, and the number of withdrawals due to adverse events. Initially, traditional pairwise meta-analysis was performed by using a random-effects model. Then, we performed network meta-analysis to compare different therapies by using frequentist approach. Results: A total of 22 trials (5255 participants) were identified. By direct comparison, TwHF was superior to sulphasalazine according to ACR 20, 50 and 70. TwHF was superior to placebo according to ACR 20 and 50. By indirect comparisons, TwHF was superior to methotrexate, leflunomide, sulphasalazine, tacrolimus, minocycline and placebo according to ACR 20. Ranking by the Surface under the Cumulative Ranking curve (SUCRA) values showed that TwHF had the greatest probability for being the best treatment option according to ACR 20 (92.0 %) and ACR 50 (81.3 %), and the highest probability to be in the second (57.8 %) ranking position after leflunomide (69.6 %) according to ACR 70. By both direct and indirect comparisons, TwHF caused no more significant withdrawals than the placebo. The SUCRA values showed that TwHF had the highest probability to rank sixth (26.7 %) after the placebo (45.6 %) in causing withdrawals. Conclusions: Our data suggest that TwHF is effective and safe in the treatment of RA and has better clinical efficacy in terms of ACR 20 and 50 than existing conventional synthetic DMARDs. In the absence of head-to-head treatment comparison, the confidence in these estimates is low. Future comparative efficacy studies are warranted.