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% (11/25) of mesalamine patients (1 study, 55 participants; RR 1.97, 95% CI 1.24 to 3.13; GRADE = low). There was no difference between the two treatments with respect to adverse events (RR 0.69, 95% CI 0.43 to 1.10; GRADE = low), withdrawals due to adverse events (RR 0.09, 95% CI 0.01 to 1.65; GRADE = low) and serious adverse events (RR 0.12, 95% CI 0.01 to 2.21; GRADE = low). Clinical response occurred in 44% (11/25) of mesalamine patients (3 g/day) compared to 59% (22/37) of placebo patients (1 study; 62 participants; RR 0.74, 95% CI 0.44 to 1.24; GRADE = low). Histological response was observed in 44% (11/25) and 51% (19/37) of patients receiving mesalamine and placebo, respectively (1 study; 62 participants; RR 0.86, 95% CI 0.50 to 1.47; GRADE = low). There was no difference between the two treatments with respect to adverse events (RR 1.26, 95% CI 0.84 to 1.88; GRADE = low), withdrawals due to adverse events (RR 5.92, 95% CI 0.70 to 49.90; GRADE = low) and serious adverse events (RR 4.44, 95% CI 0.49 to 40.29; GRADE = low). Clinical response occurred in 63% (5/8) of prednisolone (50 mg/day for 2 weeks) patients compared to 0% (0/3) of placebo patients (1 study, 11 participants; RR 4.89, 95% CI 0.35 to 68.83; GRADE = very low). Clinical response occurred in 29% (6/21) of patients who received probiotics (2 capsules containing 0.5 x 10 CFU each of L. acidophilus LA-5 and B. animalis subsp. lactis strain BB-12 twice daily for 12 weeks) compared to 13% (1/8) of placebo patients (1 study, 29 participants, RR 2.29, 95% CI 0.32 to 16.13; GRADE = very low). Clinical response occurred in 73% (8/11) of patients who received mesalamine (800 mg three times daily) compared to 100% (12/12) of patients who received mesalamine + cholestyramine (4 g daily) (1 study, 23 participants; RR 0.74, 95% CI 0.50 to 1.08; GRADE = very low). Clinical response occurred in 81% (38/47) of patients who received budesonide (9 mg daily in a tapering schedule for 6 to 8 weeks) compared to 17% (8/47) of placebo patients (3 studies; 94 participants; RR 4.56, 95% CI 2.43 to 8.55; GRADE = low). Histological response was higher in budesonide participants (72%, 34/47) compared to placebo (17%, 8/47) (RR 4.15, 95% CI 2.25 to 7.66; GRADE = low). Clinical response was maintained in 68% (57/84) of budesonide patients compared to 20% (18/88) of placebo patients (3 studies, 172 participants, RR 3.30 95% CI 2.13 to 5.09; GRADE = low). Histological response was maintained in 48% (19/40) of budesonide patients compared to 15% (6/40) of placebo patients (2 studies; 80 participants; RR 3.17, 95% CI 1.44 to 6.95; GRADE = very low). No difference was found between budesonide and placebo for adverse events (5 studies; 290 participants; RR 1.18, o95% CI 0.92 to 1.51; GRADE = low), withdrawals due to adverse events (5 studies, 290 participants; RR 0.97, 95% CI 0.43 to 2.17; GRADE = very low) or serious adverse events (4 studies, 175 participants; RR 1.11, 95% CI 0.15 to 8.01; GRADE = very low). Adverse effects reported in the budesonide studies include nausea, vomiting, neck pain, abdominal pain, excessive sweating and headache. Adverse effects reported in the mesalamine studies included nausea and skin rash. Adverse effects in the prednisolone study included abdominal pain, headache, sleep disturbance, mood change and weight gain.

AUTHORS' CONCLUSIONS: Low quality evidence suggests that budesonide may be effective for inducing and maintaining clinical and histological response in patients with collagenous colitis. We are uncertain about the benefits and harms of therapy with bismuth subsalicylate, Boswellia serrata extract, mesalamine with or without cholestramine, prednisolone and probiotics. These agents and other therapies require further study.