Interventions for treating microscopic colitis: a Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Review Group systematic review of randomized trials.

OBJECTIVES: To conduct a systematic review to determine effective treatments for patients with collagenous colitis or lymphocytic colitis, the two subtypes of microscopic colitis.
METHODS: Relevant papers were identified via the MEDLINE, PUBMED, and Cochrane Collaboration databases, manual searches of the references of identified papers and review papers on microscopic colitis, as well as searches of abstracts from major gastroenterological meetings.
RESULTS: All studies assessing treatment of microscopic colitis had relatively small sample sizes. A total of 10 randomized trials included patients with collagenous colitis. Budesonide was studied for induction of response in three trials and for maintenance of response in two trials. The pooled odds ratio for inducing clinical response with budesonide was 12.32 (95% confidence interval, CI 5.53-27.46), and for maintaining clinical response was 8.82 (95% CI 3.19-24.37), with a number needed to treat (NNT) of 2 patients for each outcome. Budesonide also induced and maintained histological response and was well tolerated. Bismuth subsalicylate, prednisolone, and mesalamine with or without cholestyramine may be effective, whereas Boswellia serrata extract and probiotics were ineffective for treating collagenous colitis. Three randomized trials included patients with lymphocytic colitis. Budesonide was shown in one study to be effective for inducing clinical response (OR 9.00; 95% CI 1.98-40.93), with an NNT of three patients. Budesonide also induced histological response and was well tolerated. Bismuth subsalicylate and mesalamine with or without cholestyramine may be effective for treating lymphocytic colitis. No trials assessed maintenance of response in patients with lymphocytic colitis.
CONCLUSIONS: Budesonide is effective and well tolerated for inducing and maintaining clinical and histological responses in patients with collagenous colitis, and for inducing clinical and histological responses in patients with lymphocytic colitis. Determining the magnitude of benefit is limited by the small sample sizes of the studies. The evidence for other agents, including bismuth subsalicylate, prednisolone, B. serrata extract, probiotics, and mesalamine with or without cholestyramine is weaker. It is not clear that any of these agents induce or maintain actual remission of collagenous or lymphocytic colitis, as opposed to clinical or histological response.