The impact of normalization of histology on disease course in microscopic colitis: a retrospective cohort study

Microscopic colitis (MC) is a colonic inflammatory bowel disease diagnosed via histology. There are no universally accepted guidelines defining treatment goals in MC. Our study evaluated the prognostic significance of histologic normalization in MC.

This retrospective cohort study identified patients with histologically confirmed MC who had at least one repeat colonoscopy with available histology. Outcomes included medical therapy use (anti-diarrheals, steroids, mesalamine, and immunosuppressants), hospitalizations, and surgeries (1) prior to or during first repeat colonoscopy or (2) after first repeat colonoscopy. Multivariable adjusted models were created for medical therapy use after first repeat colonoscopy.

This study included 380 MC patients. On first repeat colonoscopy, 164 (43.2%) patients normalized by histology and were more likely than those with persistent MC changes to have lymphocytic colitis (56.7% vs 43.3%, P = .036). There were no differences in hospitalization or surgery rates before or after first repeat colonoscopy for patients who normalized and those who did not. When compared to patients with MC at first repeat colonoscopy, those who normalized had statistically significant lower odds of steroids use after their first repeat colonoscopy (OR 0.26; 0.13-0.53) after multivariate adjustment. This association remained significant when restricted to patients with symptoms at first repeat colonoscopy (OR 0.22; 0.08-0.59) but was weaker for patients without symptoms (OR 0.45; 0.16-1.29).

In patients with MC, histologic normalization at first repeat colonoscopy was associated with reduced need for corticosteroids on follow-up. The effect was slightly attenuated in asymptomatic patients. Future studies of histologic normalization as a treatment target in MC are warranted.