Clinical characteristics and patterns and predictors of response to therapy in collagenous and lymphocytic colitis.

BACKGROUND: Collagenous colitis (CC) and lymphocytic colitis (LC) are chronic inflammatory disorders of the colon. There is a paucity of data on differences in etiology, natural history, and treatment response between CC and LC. METHODS: Between 2002 and 2013, we identified new diagnoses of CC and LC using the Research Patient Data Registry in a tertiary referral center. We used chi square or Fischer's exact test and Wilcoxon rank-sum tests to compare the differences in clinical characteristics, treatment types, and response rates between LC and CC. RESULTS: Through 2013, we confirmed 131 patients with a new diagnosis of microscopic colitis (MC) (55 LC, 76 CC). Compared to cases of LC, patients with a diagnosis of CC were more likely to be women (86% vs. 69%, p = 0.03), have elevated erythrocyte sedimentation rate (mean 28 vs. 13 mm/h, p = 0.04), and less likely to be diabetic (5% vs. 18%, p = 0.02). Budesonide was the most effective treatment for both CC and LC (94% and 80%, respectively). However, there were no statistically significant differences in response to various treatments according to the type of MC (all p > 0.10). Older age at the time of diagnosis was associated with better response to bismuth subsalicylate (odds ratio: 1.76; 95% confidence interval: 1.21-2.56 for every 5-year increase) for both CC and LC. CONCLUSION: Despite differences in the clinical characteristics, response rates to available treatments appeared to be similar in both LC and CC. Older patients may have a better response to bismuth subsalicylate therapy.