Background: Ulcerative colitis (UC) is a chronic inflammatory condition of the colon characterized by episodes of disease activity and symptom-free remission.There is paucity of evidence regarding the efficacy and safety of complementary or alternative medicines for the management of UC. Curcumin, an anti-inflammatory agent, has been used in many chronic inflammatory conditions such as rheumatoid arthritis, esophagitis and post-surgical inflammation. The efficacy of this agent for maintenance of remission in patients with UC has not been systematically evaluated.
Objectives: The primary objective was to systematically review the efficacy and safety of curcumin for maintenance of remission in UC.
Search methods: A computer-assisted literature search of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and the Cochrane Inflammatory Bowel Disease Specialized Trial Register was performed on July 11, 2012 to identify relevant publications. Proceedings from major gastroenterology meetings and references from published articles were also searched to identify additional studies.
Selection criteria: Randomized placebo-controlled trials (RCT) of curcumin for maintenance of remission in UC were included. Studies included patients (of any age) who were in remission at the time of recruitment. Co-interventions were allowed.
Data collection and analysis: Two authors independently extracted data and assessed the methodological quality of the included studies using the Cochrane risk of bias tool. Data were analyzed using Review Manager (RevMan 5.1). We calculated the relative risk (RR) and 95% confidence interval (95% CI) for each dichotomous outcome. For continuous outcomes we calculated the mean difference (MD) and 95% CI.
Main results: Only one trial (89 patients) fulfilled the inclusion criteria. This trial randomized 45 patients to curcumin and 44 patients to placebo. All patients received treatment with sulfasalazine or mesalamine. The study was rated as low risk of bias. Curcumin was administered orally in a dose of 2 g/day for six months. Fewer patients relapsed in the curcumin group than the placebo group at six months. Four per cent of patients in the curcumin group relapsed at six months compared to 18% of patients in the placebo group (RR 0.24, 95% CI 0.05 to 1.09; P = 0.06). There was no statistically significant difference in relapse rates at 12 months. Twenty-two per cent of curcumin patients relapsed at 12 months compared to 32% of placebo patients (RR 0.70, 95% CI 0.35 to 1.40; P = 0.31). A total of nine adverse events were reported in seven patients. These adverse events included sensation of abdominal bulging, nausea, transient hypertension, and transient increase in the number of stools. The authors did not report which treatment group the patients who experienced adverse events belonged to. The clinical activity index (CAI) at six months was significantly lower in the curcumin group compared to the placebo group (1.0 + 2.0 versus 2.2 + 2.3; MD -1.20, 95% CI -2.14 to -0.26). The endoscopic index (EI) at six months was significantly lower in the curcumin group than in the placebo group (0.8 + 0.6 versus 1.6 + 1.6; MD -0.80, 95% CI -1.33 to -0.27).
Authors' conclusions: Curcumin may be a safe and effective therapy for maintenance of remission in quiescent UC when given as adjunctive therapy along with mesalamine or sulfasalazine. However, further research in the form of a large scale methodologically rigorous randomized controlled trial is needed to confirm any possible benefit of curcumin in quiescent UC.