Bariatric Bypass Surgery Is a Risk Factor for Incomplete Colonoscopy Preparation

Effective colon cancer screening requires adequate bowel preparation. Anecdotal evidence has suggested that patients with a history of bariatric surgery are more likely to have inadequate preparation. This study aims to evaluate the role of bariatric surgery as a predictive risk factor for inadequate bowel preparation.

Data were collected retrospectively for consecutive colonoscopies between March 1, 2013, and November 15, 2017. Only the index colonoscopy for each patient within the review period, and those scored using the Boston Bowel Preparation Scale (BBPS) were included. Inadequate preparation was defined as any one or more colon segments with a BBPS score of less than two, and patients with a history of bariatric surgery were identified using ICD 9/10 codes. Multivariate logistic regression and propensity score matching was used to assess for independent factors predictive of inadequate bowel preparation.

A total of 25,318 colonoscopies were included in the analysis. Two hundred 278 (1.1%) patients had a history of bariatric surgery, among which 171 (61.5%) had a history of bypass surgery and 107 (38.5%) had a history of restrictive surgical procedure. A history of bariatric surgery was predictive of inadequate bowel preparation in both univariate (OR: 2.87, 95% CI: 1.92-4.29, P = 0.0003) and multivariate analysis (OR: 2.16, 95% CI: 1.43-3.27, P = 0.0003) after controlling for differences in baseline characteristics. When evaluated separately, a history of bypass surgery was associated with inadequate bowel preparation (aOR: 2.96, 95% CI: 1.86-4.72, P < 0.0001), whereas a history of a restrictive bariatric surgery was not associated with inadequate bowel preparation in multivariate analysis (aOR: 0.98, 95% CI: 0.4-2.45, P = 0.971).

A history of bariatric surgery is an independent risk factor for inadequate bowel preparation. Furthermore, bypass bariatric surgeries had higher rates of inadequate preparation when compared to restrictive bariatric surgeries. Further quality improvement initiatives should be directed at identifying the appropriate bowel preparation regimen in this population.