Risk interval analysis of emergency room visits following colonoscopy in patients with inflammatory bowel disease

PLoS One. 2019 Jan 9;14(1):e0210262. doi: 10.1371/journal.pone.0210262. eCollection 2019.


Background and aims: Prior studies suggest that colonoscopy may exacerbate inflammatory bowel disease (IBD) symptoms. Thus, our study aimed to determine risk of emergency room (ER) visits associated with colonoscopy among IBD patients and evaluate potential modifiers of this risk.

Methods: The study population included IBD patients in the Multi-Payer Claims Database who were >20 years old and had a colonoscopy from 2007-2010. We used a self-controlled risk interval design and mixed-effects Poisson regression models to calculate risk ratios (RR) and 95% confidence intervals (CI) comparing the incidence of ER visits in the 1-4 weeks following colonoscopy (risk interval) to the incidence of ER visits in the 7-10 weeks after colonoscopy (control interval). We also conducted stratified analyses by patient characteristics, bowel preparation type, and medication.

Results: There were 212,205 IBD patients with at least 1 colonoscopy from 2007-2010, and 3,699 had an ER visit during the risk and/or control interval. The risk of an ER visit was higher in the 4-week risk interval following colonoscopy compared to the control interval (RR = 1.24; 95% CI: 1.17-1.32). The effect was strongest in those <41 years old (RR = 1.60; 95% CI: 1.21-2.11), in women (RR = 1.32; 95% CI: 1.21-1.44), and in those with sodium phosphate bowel preparation (RR = 2.09; 95% CI: 1.02-4.29). Patients using immunomodulators had no increased risk of ER visits (RR = 0.75; 95% CI: 0.35-1.59).

Conclusions: Our results suggest that there is an increased risk of ER visits following colonoscopy among IBD patients, but that immunomodulators and mild bowel preparation agents may mitigate this risk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Colonoscopy / adverse effects*
  • Emergency Service, Hospital / statistics & numerical data*
  • Female
  • Humans
  • Iatrogenic Disease / epidemiology
  • Iatrogenic Disease / prevention & control*
  • Immunologic Factors / pharmacology*
  • Incidence
  • Inflammatory Bowel Diseases / diagnosis*
  • Male
  • Middle Aged
  • Risk Factors
  • United States / epidemiology
  • Young Adult


  • Immunologic Factors