Budesonide Versus Mesalamine in Microscopic Colitis: A Comparative Meta-analysis of Randomized Controlled Trials.

Background: Microscopic colitis (MC) is an inflammatory bowel disease of autoimmune origin that causes chronic watery diarrhea. Medications, including budesonide, mesalamine, loperamide, cholestyramine, and bismuth subsalicylate, are first-line therapies. Meanwhile, azathioprine, 6-mercaptopurine, and methotrexate are indicated for refractory MC.

Objective: We aim to assess the efficacy and safety of budesonide compared with mesalamine for induction of remission in MC patients.

Methods: We searched the Cochrane Library, Scopus, Web of Science, and PubMed for relevant clinical trials comparing either mesalamine or budesonide with a control group. We included the following outcomes: clinical remission (3 or fewer stools/day), daily stool weight, daily stool frequency, number of patients with clinical response <50% in the disease activity, and daily stool consistency. Safety end points included: any adverse event, serious adverse events, any adverse event-related discontinuation, abdominal discomfort, constipation, flatulence, nausea, dizziness, headache, bronchitis, nasopharyngitis, and depression. We conducted a meta-analysis model using the generic inverse variance method and performed a subgroup analysis based on the intervention administered.

Results: Nineteen randomized clinical trials were included. We found that after 6 weeks of follow-up, budesonide is associated with increased clinical remission rates compared with mesalamine [RR=2.46 (2.27, 2.67), and RR=2.24 (1.95, 2.57), respectively]. However, the test of subgroup difference revealed that the difference is not significant (P=0.25). After 8 weeks of follow-up, budesonide showed significantly higher clinical remission rates than mesalamine RR=2.29 (2.14, 2.45), and RR=1.7 (1.41, 2.05), respectively (P=0.003). Regarding the daily stool weight, patients in the budesonide group showed nonsignificant less stool weight [MD=-351.62 (-534.25, -168.99)] compared with mesalamine [MD=-104.3 (-372.34, 163.74)], P=0.14. However, daily stool frequency was significantly less in the budesonide group compared with mesalamine (P<0.001). Budesonide is associated with a significantly lower incidence of adverse events compared with mesalamine (P=0.002). Analysis of other safety endpoints was not significant between both groups.

Conclusions: Budesonide was found to be better than mesalamine in MC patients in terms of clinical remission rate, especially after 8 weeks of follow-up. Budesonide also showed less incidence of adverse events. There is an urgent need for randomized, double-blinded clinical trials to provide direct and reliable evidence.