BACKGROUND

Collagenous colitis is 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 collagenous colitis.

SEARCH STRATEGY

Relevant papers published between 1970 and December 2007 were identified via the MEDLINE and PUBMED 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 and Functional Bowel Disorders Group Specialized Trials Register were searched for other studies.

SELECTION CRITERIA

Ten randomized trials were identified. Seven of these compared active treatment to placebo for treating active disease. Of these, 1 trial studied bismuth subsalicylate, 1 trial studied Boswellia serrata extract, 3 trials studies budesonide, 1 trial studied prednisolone, and 1 trial studied probiotics. One trial compared mesalamine to mesalamine + cholestyramine for treating active disease. Two trials compared budesonide to placebo in maintaining response induced by budesonide.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by each author onto 2x2 tables (treatment versus comparator 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

In treating active disease, there were 9 patients with collagenous colitis in the trial studying bismuth subsalicylate (nine 262 mg tablets daily for 8 weeks). Clinical response occurred in 100% of patients who received bismuth subsalicylate compared to 0% of patients who received placebo (P = 0.03). Thirty-one patients were enrolled in the trial studying Boswellia serrata extract (three 400 mg capsules daily for 8 weeks). Clinical response occurred in 44% of patients who received Boswellia serrata extract compared to 27% of patients who received placebo (P = 0.32). A total of 94 patients were enrolled in 3 trials studying budesonide (9 mg daily or in a tapering schedule for 6 to 8 weeks). Clinical response occurred in 81% of patients who received budesonide compared to 17% of patients who received placebo (P < 0.00001). The pooled odds ratio for clinical response to treatment with budesonide was 12.32 (95% CI 5.53 to 27.46), with a number needed to treat of 2 patients. Statistically significant histological response occurred with treatment in all 3 trials studying budesonide therapy. Eleven patients were enrolled in the trial studying prednisolone (50 mg daily for 2 weeks). Clinical response occurred in 63% of patients who received prednisolone compared to 0% who received placebo (P = 0.15). Twenty-nine patients were enrolled in the trial studying probiotics (2 capsules containing 0.5 x 10(10) CFU each of L. acidophilus LA-5 and B. animalis subsp. lactis strain BB-12 twice daily for 12 weeks). Clinical response occurred in 29% of patients who received probiotics compared to 13% of patients who received placebo (P = 0.38). Twenty-three patients were enrolled in the trial studying mesalamine (800 mg three times daily) with or without cholestyramine (4 g daily) for 6 months. Clinical response occurred in 73% of patients who received mesalamine alone compared to 100% of patients who received mesalamine + cholestyramine (P = 0.14). In maintaining response, 80 patients who had responded to open-label budesonide were enrolled in 2 trials studying budesonide (6 mg daily for 6 months). Clinical response was maintained in 83% of patients who received budesonide compared to 28% of patients who received placebo (P = 0.0002). The pooled odds ratio for maintenance of clinical response to treatment with budesonide was 8.40 (95% CI 2.73 to 25.81), with a number needed to treat of 2 patients. Histological response was maintained in 48% of patients who received budesonide compared to 15% of patients who received placebo (P = 0.002).

AUTHORS' CONCLUSIONS: Budesonide is effective for inducing and maintaining clinical and histological response in patients with collagenous colitis. The evidence for benefit with bismuth subsalicylate and for mesalamine with or without cholestyramine is weak. There is no evidence for the effectiveness of Boswellia serrata extract, prednisolone, or probiotics. These agents and other therapies require further study.