Efficacy and Safety of Runzao Zhiyang Capsule as an Add-On Therapy for Chronic Eczema: A Systematic Review and Meta-Analysis

Background. Runzao Zhiyang capsule (RZC), an oral Chinese herbal medicine, has been widely used for chronic eczema in China for many years. This study aims to evaluate the efficacy and safety of RZC as an add-on therapy to conventional treatment for chronic eczema. Methods. Randomized controlled trials (RCTs) assessing the efficacy and safety of RZC as an add-on therapy for chronic eczema were retrieved from eight literature databases from their inception to 31 August, 2020, including CNKI, WanFang, VIP, Sinomed, PubMed, Cochrane Library, Web of Science, and Embase. The Cochrane risk of bias tool was used to assess the methodological quality of the included studies. The data were analyzed by RevMan5.3 software. Results. A total of 18 RCTs involving 1896 patients with chronic eczema were included. Compared with no oral treatment, RZC was superior on the total efficacy rate (TER) (RR = 1.45, 95% CI: 1.23 to 1.72, $P<0.0001$ ), Eczema Area and Severity Index (EASI) (MD = −0.73, 95% CI: −0.90 to −0.56, $P<0.00001$ ), and Visual Analogue Scale (VAS) for pruritus (MD = −2.76, 95%CI: −4.53 to −0.99, $P=0.002$ ). Similar results were also seen in a randomized, placebo-controlled trial. Compared with the antihistamine (AH) group, TER in the RZC combined with AH group was significantly higher (RR = 1.32, 95% CI: 1.21 to 1.43, $P<0.00001$ ), and the EASI score (MD = −0.29, 95% CI: −0.38 to −0.20, $P<0.001$ ), the VAS score (MD = −0.19, 95% CI: −0.23 to −0.15, $P<0.00001$ ), and the level of serum total IgE (MD = −9.83 ng/ml, 95% CI: −11.66 to −8.00 ng/ml, $P<0.00001$ ) decreased more significantly in the RZC combined with AH group. In terms of safety, mild gastrointestinal diseases occurred more frequently in the RZC group, and no serious adverse effect was reported. Conclusions. RZC as an add-on therapy to conventional treatment shows good effects on chronic eczema, and there is no severe side effect from short-term use of RZC. However, due to suboptimal quality of the included studies, more large-sample and high-quality RCTs are needed to improve the evidence quality.