Efficacy and safety of compound glycyrrhizin in combination with conventional therapy in treatment of vitiligo: A systematic review and meta-analysis of randomized controlled trials

Background: Vitiligo is an acquired chronic depigmentary disorder affecting approximately 0.5% to 1% of individuals worldwide. The compound glycyrrhizin (CG), a complementary medicine, has been reported for treatment of vitiligo, but the evidence has not been systematically evaluated. We systematically assessed the efficacy and safety of CG in combination with conventional therapy for the treatment of vitiligo.Methods: We searched Embase, Web of Science, PubMed, The Cochrane Library, Chinese BioMedical Literature Database (CBM), Wanfang Data, China National Knowledge Infrastructure (CNKI), and VIP information from inception to July 2022. Randomized controlled trials comparing CG combined with conventional therapy with conventional therapy alone for vitiligo were included in our analysis. The primary outcome was treatment response, which defined as >50% repigmentation rate of vitiligo after treatment. The secondary outcome was incidence of adverse events. Meta-analysis was performed using the Review Manager 5.4 software. Statistical heterogeneity was evaluated with chi-square and I2 statistics, dichotomous data were expressed as risk ratios (RR) with 95% confidence intervals using the Mantel-Haenszal method.Results: Thirty-nine studies enrolling with 3994 participants were subjected to this review. The results of our meta-analysis indicated that addition of CG had superior effectiveness on repigmentation rate than phototherapy (RR = 1.28; P < .001), immunosuppressant (RR = 1.76; P < .001), traditional Chinese medicine (RR = 1.38; P < .001), combination of phototherapy and immunosuppressant (RR = 1.42; P < .001), and combination of phototherapy and traditional Chinese medicine (RR = 1.37; P < .001). In addition, CG did not increase the incidence of adverse events for vitiligo (RR = 0.79; P = .05).Conclusions: CG as a complementary medicine has a potential benefit in treatment of vitiligo. However, since the methodological flaws in the studies we included, more high-quality randomized controlled trials are warranted.