Background: Collagenous colitis is a disorder that is recognized as a cause of chronic diarrhea. Treatment has been based mainly on anecdotal evidence. This review was performed to identify therapies for collagenous colitis that have been proven in randomized trials.
Objectives: To determine effective treatments for patients with clinically active collagenous colitis.
Search strategy: Relevant papers published between 1970 and January 2002 were identified via the MEDLINE, PUBMED, and EMBASE databases. Manual searches from the references of identified papers, as well as review papers on collagenous or microscopic colitis were performed to identify additional studies. Abstracts from major gastroenterological meetings were searched to identify research submitted in abstract form only. Finally, the Cochrane Controlled Trials Register and the Cochrane Inflammatory Bowel Disease Group Specialized Trials Register were searched for other studies.
Selection criteria: Four randomized trials were identified. One trial studied bismuth subsalicylate (published in abstract form only), and 3 trials (2 published in abstract form only) studied budesonide in the therapy of collagenous colitis.
Data collection and analysis: Data were extracted independently by each author onto 2x2 tables (treatment versus placebo and response versus no response). For therapies assessed in one trial only, p-values were derived using the chi-square test. For therapies assessed in more than one trial, summary test statistics were derived using the Peto odds ratio and 95% confidence intervals. Data were combined for analysis only if the outcomes were sufficiently similar in definition.
Main results: There were 9 patients with collagenous colitis in the trial studying bismuth subsalicylate (nine 262 mg tablets daily for 8 weeks). Those randomized to active drug were more likely to have clinical (p=0.003) and histological (p=0.003) improvement than those assigned to placebo. A total of 86 patients were enrolled in 3 trials studying budesonide (9 mg daily for 6 to 8 weeks). The pooled odds ratio for clinical response to treatment with budesonide was 16.79 (95% CI 7.28-38.74), with a number needed to treat of 2 patients. There was significant histological improvement with treatment in all 3 trials studying budesonide therapy.
Reviewer's conclusions: Budesonide is effective in the treatment of collagenous colitis. The evidence for bismuth subsalicylate is weaker, but still important. The roles of these and other therapies in inducing or maintaining remission (as opposed to clinical or histological improvement) of collagenous colitis are unknown.