Clinical Characteristics and Treatment Response in Microscopic Colitis Based on Age at Diagnosis: A Multicenter Retrospective Study

BACKGROUND: Microscopic colitis (MC) primarily affects older adults; thus, data in younger patients are scarce. AIMS: To compare clinical characteristics and treatment response by age at diagnosis. METHODS: This retrospective cohort study was performed at Mayo Clinic and Massachusetts General Hospital. Patients were chosen consecutively using established databases. Patients were ‘younger’ if age at diagnosis was ≤ 50 years and ‘older’ if age > 50 years. Treatment outcomes were captured for induction (12 ± 4 weeks), based on the total number of daily stools, and defined as remission (complete resolution), response (≥ 50% improvement), non-response (< 50% improvement), and intolerance. Patients were considered ‘responders’ if they had remission or response and ‘non-responders’ if they had non-response or intolerance. RESULTS: We included 295 patients (52 younger, 243 older). There were no differences in sex, race, MC subtype, and diarrhea severity between groups (all P > 0.05). Younger patients were more likely to have celiac disease (17.3% vs. 5.8%, P = 0.01), while older patients had higher BMI (mean 25.0 vs. 23.8 kg/m(2), P = 0.04) were more likely smokers (53.9% vs. 34.6%, P = 0.01) and use NSAIDs (48.6% vs. 15.4%, P < 0.01) and statins (22.6% vs. 3.8%, P < 0.01). Overall treatment response was highest for budesonide (88.3%) and did not differ when comparing older to younger patients (90.6% vs. 77.8%, P = 0.12) or by MC subtype (LC, 81.5% vs. CC, 92.9%, P = 0.07). CONCLUSIONS: There are no significant differences in MC treatment response based on age or disease subtype. These findings support treating patients with MC based on symptom severity rather than age. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10620-021-07162-4.