title: Adverse events after screening and follow-up colonoscopy.
abstract: OBJECTIVE
  We provide new information about how the risk of adverse events following colonoscopy varies by age and indication (screening vs. follow-up performed to evaluate a positive result from another screening modality).
  
  
  METHODS
  We constructed a retrospective cohort comprised of 43,456 individuals aged 40-85 years enrolled in a large integrated healthcare organization in Washington State who underwent outpatient colonoscopy between 1994 and 2009. We calculated rates of serious adverse events (perforation, hemorrhage, and acute diverticulitis) in the 30 days following colonoscopy and compared rates using log-binomial regression models.
  
  
  RESULTS
  We observed 4.7 serious adverse events per 1,000 screening colonoscopies and 6.8 per 1,000 follow-up colonoscopies. Polypectomy increased the rate of serious adverse events (relative rate [RR], 2.64; 95% confidence interval [CI], 1.97-3.56). Older age was associated with increased risk of serious adverse events, after adjusting for polypectomy, gender, and indication. Compared to individuals aged 50-64 years, risk was elevated for those aged 65-74 (RR, 1.93; 95% CI, 1.40-2.65) and 75-85 (RR, 3.21; 95% CI 2.14-4.86). We observed similar age effects in individuals with and without significant comorbid conditions.
  
  
  CONCLUSIONS
  The risks of serious adverse events following colonoscopy performed as part of screening are low but increase with age and are more likely after polypectomy.
authors: Group Health Research Institute, Seattle, WA 98101, USA. rutter.c@ghc.org
authors: Carolyn M
authors: CM
authors: Rutter
authors: Eric
authors: E
authors: Johnson
authors: Diana L
authors: DL
authors: Miglioretti
authors: Margaret T
authors: MT
authors: Mandelson
authors: John
authors: J
authors: Inadomi
authors: Diana S M
authors: DS
authors: Buist
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000554:Ambulatory Care Facilities; D015331:Cohort Studies; D003113:Colonoscopy / Q000009:adverse effects*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000009:adverse effects*; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors