WASHINGTON — Patients who are sicker, who are taking warfarin, and whose polyps are removed by snare with cautery are at higher risk for complications following screening or surveillance colonoscopy, according to an analysis presented at the annual Digestive Disease Week.
Overall, the incidence of serious complications after screening was 2.2 of every 1,000 exams, and it was 1.7/1,000 for potential related events, according to Dr. Cynthia Ko of the University of Washington, Seattle.
Dr. Ko and her colleagues prospectivelyassessed colonoscopies performed on 18,271 patients aged 40 years and older who were referred for average risk screening, surveillance of prior polyps or cancer, a family history of polyps or cancer, or follow-up after another diagnostic procedure, such as a positive result on a fecal occult blood test.
Patients were excluded if they had a history of recent gastrointestinal bleeding or of inflammatory bowel disease, or had an incomplete colonoscopy because of poor bowel preparation.
The researchers identified the study patients through the Clinical Outcomes Research Initiative, a database maintained by the Oregon Health and Science University, Portland.
Complication rates for surveillance and screening aren't well defined, Dr. Ko said. In the Washington study, patients were queried at 7 and 30 days after colonoscopy about new symptoms, physician visits, hospitalizations, and unplanned surgeries.
Related events included colon perforation, GI bleeding, diverticulitis, and postpolypectomy syndrome. Potentially related complications included cardiac and neurologic events.
The 18,271 patients came from 19 sites and received colonoscopies from 89 endoscopists. Related complication rates were 1.3/1,000 for GI bleeding requiring hospitalization, 0.8/1,000 for GI bleeding requiring transfusion, 0.9/1,000 for diverticulitis, 0.3/1,000 for diverticulitis requiring hospitalization, 0.1/1,000 for postpolypectomy syndrome, and 0.2/1,000 for perforation.
The authors also calculated an overall complication rate of 2.2/1,000, which included GI bleeding with transfusion, diverticulitis with hospitalization, perforation, or postpolypectomy syndrome. The serious complication rate was 1.4/1,000; serious complications included GI bleeding with hospitalization, diverticulitis with hospitalization, perforation, or postpolypectomy syndrome.
Potentially related events included angina or myocardial infarction (0.6/1,000), stroke or transient ischemic attack (0.4/1,000), and other events, including hospitalization for intravenous catheter site infections, abdominal pain, arrythmia, gallstones, kidney stones, and drug reactions (0.7/1,000).
Complications were higher for patients undergoing a surveillance or follow-up exam, and for those who were older. There were no complications among the 40- to 49-year-olds, compared with 4.4/1,000 among patients aged 80 and older.
There was a threefold increase in complications in patients who were American Society of Anesthesiologists class III, compared with class I or II patients; a fivefold increase in patients who took warfarin, compared with those who used aspirin or NSAIDs; and a fivefold increase for a polyp removed with cautery. If more than one polyp was removed, there was a 13-fold increase in complications, Dr. Ko said.
The study was supported by the National Institutes of Health and the Centers for Disease Control and Prevention.