Interventions for treating collagenous colitis

Background Collagenous colitis is a cause of chronic diarrhea. This updated review was performed to identify therapies for collagenous colitis that have been assessed in randomized controlled trials (RCTs). Objectives The primary objective was to assess the benefits and harms of treatments for collagenous colitis. Search methods We searched CENTRAL, the Cochrane IBD Group Specialized Register, MEDLINE and EMBASE from inception to 7 November 2016. Selection criteria We included RCTs comparing a therapy with placebo or active comparator for the treatment of active or quiescent collagenous colitis. Data collection and analysis Data were independently extracted by two authors. The primary outcome was clinical response or maintenance of response as defined by the included studies. Secondary outcome measures included histological response, quality of life and the occurrence of adverse events. Risk ratios (RR) and 95% confidence intervals (CI) were calculated for dichotomous outcomes. The Cochrane risk of bias tool was used to assess bias. The overall quality of the evidence was assessed using the GRADE criteria. Main results Twelve RCTs (476 participants) were included. These studies assessed bismuth subsalicylate, Boswellia serrata extract, mesalamine, cholestyramine, probiotics, prednisolone and budesonide therapy. Four studies were low risk of bias. One study assessing mesalamine and cholestyramine was judged to be high risk of bias due to no blinding. The other studies had an unclear risk of bias for random sequence generation (five studies) allocation concealment (six studies), blinding (one study), incomplete outcome data (one study) and selective outcome reporting (one study). Clinical response occurred in 100% (4/4) of patients who received bismuth subsalicylate (nine 262 mg tablets daily for 8 weeks) compared to 0% (0/5) of patients who received placebo (1 study; 9 participants; RR 10.80, 95% CI 0.75 to 155.93; GRADE = very low). Clinical response occurred in 44% (7/16) of patients who received Boswellia serrata extract (three 400 mg/day capsules for 8 weeks) compared to 27% (4/15) of patients who received placebo (1 study; 31 participants; RR 1.64, 95% CI 0.60 to 4.49; GRADE = low). Clinical response occurred in 80% (24/30) of budesonide patients compared to 44% (11/25) of mesalamine patients (1 study; 55 participants; RR 1.82, 95% CI 1.13 to 2.93; GRADE = low). Histological response was observed in 87% (26/30) of budesonide patients compared to 44% (1