Patient tolerability of bowel preparation is associated with polyp detection rate during colonoscopy

A number of factors have been identified that influence the yield of screening colonoscopy. The perceived tolerability of bowel preparation has not been studied as a predictor of quality outcomes in colonoscopy. We aimed to characterize the association between patient-perceived tolerability of bowel preparation and polyp detection during colonoscopy.

We performed a cross-sectional cohort study of 413 consecutive adult patients presenting for outpatient colonoscopy at two outpatient endoscopy centers at our institution. We developed a standardized questionnaire to assess the patient's experience with bowel preparation. Bowel preparation quality was measured using the validated Ottawa scale and colonoscopic findings were recorded for each patient. The primary outcome was polyp detection and the secondary outcome was the quality of bowel preparation.

Patient-reported clarity of effluent during bowel preparation correlated poorly with Ottawa score during colonoscopy, ĸ=0.15. Female gender was an independent risk factor for a poorly tolerated bowel prep (OR 3.93, 95% CI 2.30 - 6.72, p<0.001). Report of a poorly tolerated bowel prep was independently associated with the primary outcome, polyp detection (OR 0.39, 95% CI 0.18 - 0.84, p=0.02) and also with the secondary outcome, lower quality bowel preparation (OR 2.39, 95% CI 1.17 - 4.9, p=0.02).

A patient-perceived negative experience with bowel preparation independently predicted both a lower quality bowel preparation and a lower rate of polyp of detection. Assessment of the tolerability of bowel preparation before colonoscopy may be a clinically useful predictor of quality outcomes during colonoscopy.