Factors determining post-colonoscopy abdominal pain: prospective study of screening colonoscopy in 1000 subjects.

Background: Factors determining post-colonoscopy abdominal pain remain poorly understood. Accordingly, a prospective study was conducted to reveal the key determinants.

Methods: One thousand consecutive and asymptomatic patients (569 men, 431 women; mean age 51 years, range 19-84 years) undergoing total colonoscopy were evaluated to assess their abdominal pain. Their demographic data, psychological profiles (determined on the Brief Symptom Rating Scale and Maudsley Personality Inventory), and endoscopic findings were treated as independent variables in polytomous logistic regression in which pain severities were treated as outcome variables. Factors affecting the duration of pain were evaluated on multivariate linear regression.

Results: Colonoscopy duration (s; odds ratio [OR]: 1.001, 95% confidence interval [CI]: 1-1.002, P<0.01) and female sex (OR: 1.368, 95%CI: 1.02-1.853, P=0.03) were significantly associated with abdominal pain, but age, body mass index, psychological traits, conscious sedation, use of i.v. hyoscine butylbromide, and colonic preparation were not. Duration of the colonoscopy was longer in female than male subjects (P=0.04). On stepwise linear regression, irritable bowel syndrome (regression coefficient: 27.47, 95%CI: 6.99-47.67, P<0.01) and conscious sedation (regression coefficient: -22.17, 95%CI: -42.52 to -1.42, P = 0.036) were the best predictors of prolonged pain in 485 patients who had pain.

Conclusions: Female sex and duration of colonoscopy increased the likelihood of post-procedural abdominal pain. Conscious sedation temporarily suppressed the pain but had no effect on its occurrence. Irritable bowel syndrome may have prolonged the discomfort.