Impact of colonoscopy preparation quality on detection of suspected colonic neoplasia.

Background: Suboptimal bowel preparation for colonoscopy can lead to missed colonic lesions. The aim of this study was to describe the impact of preparation quality on detection of suspected colonic neoplasia.
Methods: Data from the Clinical Outcomes Research Initiative national endoscopic database for the period January 1, 2000 to December 31, 2001, were analyzed. Patient demographics, quality of preparation, and colonoscopy findings were abstracted from the database.
Results: Overall, 93,004 colonoscopies with adequate documentation were reviewed. Preparation was adequate for 71,501 (76.9%) of these procedures. On multivariate analysis, preparation adequacy was associated with colonic lesion detection, odds ratio (OR) 1.21: 95% CI [1.16, 1.25]. Adequate preparation demonstrated a closer association with identification of "nonsignificant" lesions (polyps <or=9 mm), OR 1.23: 95% CI [1.19, 1.28], compared with "significant" lesion detection (mass lesion, polyps >9 mm), OR 1.05: 95% CI [0.98, 1.11].
Conclusions: Bowel preparation is inadequate for almost a quarter of patients undergoing colonoscopy. These results suggest that inadequate preparation quality only hinders detection of smaller lesions, while having negligible impact on detection of larger lesions. These results should be confirmed in prospective studies.