The incidence of 30-day adverse events after colonoscopy among outpatients in the Netherlands

OBJECTIVES: Colonoscopy is the gold standard for visualization of the colon. It is generally accepted as a safe procedure and major adverse events occur at a low rate. However, few data are available on structured assessment of (minor) post-procedural adverse events. METHODS: Consecutive outpatients undergoing colonoscopy were asked for permission to be called 30 days after their procedure. A standard telephone interview was developed to assess the occurrence of (i) major adverse events (hospital visit required), (ii) minor adverse events, and (iii) days missed from work. Adverse events were further categorized in definite-, possible-, and unrelated adverse events. Patients were contacted between January 2010 and September 2010. RESULTS: Out of a total of 1,528 patients who underwent colonoscopy and gave permission for a telephone call, 1,144 patients were contacted (response: 75%), 49% were male, the mean age was 59 years (s.d.: 14). Thirty-four patients (3%) reported major adverse events. These were definite-related in nine (1%) patients, possible-related in 6 (1%), and unrelated in 19 patients (2%). Minor adverse events were reported by 466 patients (41%). These were definite-related in 336 patients (29%), possible-related in 36 (3%), and unrelated in the remaining 94 patients (8%). Female gender (odds ratio (OR): 1.5), age <50 years (OR: 1.5), colonoscopy for colorectal cancer screening/surveillance (OR: 1.6), and fellow-endoscopy (OR: 1.7) were risk factors for the occurrence of any definite-related adverse event. Patients who reported definite-related adverse events were significantly less often willing to return for colonoscopy (81 vs. 88%, P<0.01) and were less often positive about the entire colonoscopy experience (84 vs. 89%, P=0.04). CONCLUSIONS: Structured assessment of post-colonoscopy adverse events shows that these are more common than generally reported. Close to one-third of patients report definite-related adverse events, which are major in close to 1 in 100 patients. The occurrence of adverse events does have an impact on the willingness to return for colonoscopy.