Efficacy of adjuvant curcumin therapy in ulcerative colitis: A meta-analysis of randomized controlled trials

Background and Aim Aminosalicylic acids are recognized to be the first-line treatment options for ulcerative colitis. Currently, the effectiveness of curcumin as an adjuvant treatment in ulcerative colitis has been investigated, which was still controversial. This study aimed to systematically review and meta-analyze the efficacy and safety of curcumin as an adjuvant treatment in ulcerative colitis. Methods The PubMed, EMBASE, and Cochrane Library databases were searched from original to July 2019, and relevant randomized controlled clinical trials were enrolled and analyzed. The primary outcomes were clinical and endoscopic remission; meanwhile, the secondary outcomes were clinical and endoscopic improvement. Subgroup analyses of doses, delivery way, form, and intervention time of curcumin were also conducted. Results Six randomized controlled clinical trials with a total of 349 patients were included. Eligible trials suggested that adjuvant curcumin treatment in ulcerative colitis was effective in inducing clinical remission (odds ratio [OR] = 5.18, 95% confidence interval [CI]: 1.84-14.56, P = 0.002), endoscopic remission (OR = 5.69, 95% CI: 1.28-25.27, P = 0.02), and endoscopic improvement (OR = 17.05, 95% CI: 1.30-233.00, P = 0.03), but not in clinical improvement (OR = 4.79, 95% CI: 1.02-22.43, P = 0.05). We can see the potential advantages in large dosage, topical enema, special drug form, and longer duration from the enrolled studies. There were no severe side effects reported. Conclusions Curcumin, as an adjuvant treatment of mesalamine, was proved to be effective and safe in ulcerative colitis. Better efficacy can be achieved with suitable dose, delivery way, formation, and intervention time, which needs further study to verify.