Medications as Risk Factors for Microscopic Colitis: Have We Been Wrong?

Microscopic colitis is a common cause of chronic diarrhea in older adults (NEJM JW Gastroenterol Dec 15 2015; [e-pub] and Gastroenterology 2016; 150:242). Several medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), proton-pump inhibitors (PPIs), and selective serotonin reuptake inhibitors (SSRIs), are widely considered to be potential triggers for microscopic colitis based on observational studies, but a causal relation has not been proven.

Using data from a Swedish registry of almost 3 million older adults (ages ≥65), researchers applied a target-trial emulation framework to assess risk for biopsy-proven microscopic colitis associated with six medications. Patients who initiated NSAIDs, statins, PPIs, angiotensin-convertin…