Bile Acid Sequestrants in Microscopic Colitis: Clinical Outcomes and Utility of Bile Acid Testing

Abstract

Bile acid sequestrants (BAS) may be a treatment in microscopic colitis (MC), but efficacy data are limited. We evaluated the effectiveness of BAS in MC and assessed the utility of bile acid testing to predict response. Adults with MC treated with BAS (2010-2020) at Mayo Clinic were identified. Bile acid malabsorption was defined by elevated serum 7⍺-hydroxy-4-cholesten-3-one or by fecal testing using previously validated cutoffs. Response was defined at 12 +/- 4 weeks after BAS initiation as: complete (resolution of diarrhea), partial (≥50% improvement in diarrhea), nonresponse (<50% improvement), and intolerance (discontinuation due to side-effects). Logistic regression was used to identify predictors of response to BAS. We identified 282 patients [median age 59 (20-87) years; 88.3% women] with median follow-up 4.5 (0.4-9.1) years. Patients were treated with the following BAS: 64.9% cholestyramine, 21.6% colesevelam, and 13.5% colestipol. Clinical outcomes were: 49.3% complete response, 16.3% partial response, 24.8% nonresponse, and 9.6% intolerance. There were no differences in outcomes between those on BAS alone or BAS combined with other medications (p=0.98). The dose of BAS was not associated with response (p=0.51). Bile acid testing was done in 31.9% and 56.7% were positive. No predictors of response to BAS were identified. After BAS discontinuation, 41.6% had recurrence at a median of 21 (1-172) weeks. In one of the largest cohorts evaluating BAS treatment in MC, nearly two-thirds had a partial or complete response. Additional research is needed to determine the role of BAS and bile acid malabsorption in MC.