Ann Intern Med

Study casts doubt on link between certain meds and microscopic colitis in older adults

July 3, 2025

Study details: This nationwide Swedish study emulated six target trials using data from over 2.8 million adults aged ≥65 between 2006–2017. Researchers assessed the causal relationship between commonly implicated medications and biopsy-confirmed microscopic colitis (MC), using the Epidemiology Strengthened by histoPathology Reports in Sweden (ESPRESSO) and inverse probability weighting to estimate 12- and 24-month cumulative incidences and risk differences.

Results: Across all treatment strategies, 12- and 24-month cumulative incidences of MC were <0.5%. Risk differences were negligible for ACE inhibitors or ARBs, compared with calcium channel blockers; as well as for NSAIDs, PPIs, and statins, compared with noninitiation. A small increased risk (12-month risk difference: 0.04%, 95% confidence interval [CI]: 0.03–0.05%) was observed for SSRIs compared with mirtazapine. Several medications were also linked to increased colonoscopies with normal mucosa, suggesting potential surveillance bias.

Clinical impact: These findings challenge prior associations between common medications and MC, suggesting most don’t increase risk. Reconsider routine medication discontinuation solely to mitigate MC risk.

Source:

Khalili H, et al. (2025, July 1). Ann Intern Med. Medications and Risk for Microscopic Colitis: A Nationwide Study of Older Adults in Sweden. https://pubmed.ncbi.nlm.nih.gov/40587856/