Introduction Colonic adenoma detection is one of the quality indicators of endoscopy¹ and is measured as present or not, rather than an absolute number of adenomatous polyps per colonoscopy. Several factors are associated with higher polyp detection rate; adequate colonic distension, retroflexion in the rectum, position change, cleaning and suctioning, with slow and thorough examination of the mucosa.² The quality of bowel preparation is variable and assessed subjectively by the endoscopist. The purpose of this observational study was to determine whether more polyps are detected with good bowel preparation.

Methods All colonoscopies stored on the reporting system database (from 2004 to 2009) in a District General Hospital were identified. Completed examinations with data for both the absolute number of polyps per colonoscopy and preparation quality were included. Colonoscopies in which cancers were diagnosed, and those with missing data were excluded. Independent T-testing and χ² were used in the statistical analysis.

Results 4442 colonoscopies with complete data were identified for analysis. 3489 (78.5%) detected no polyps, and 953 (21.5%) found polyps. Polyp detection rate was not dependent on the quality of the bowel preparation (p=0.81). There was no significant difference between “good” and “poor” preparation in the mean number of polyps detected per colonoscopy (p=0.428), between “good” and “satisfactory” preparation (p=0.329), or between “satisfactory” and “poor” (p=0.936).

Conclusion The quality of bowel preparation appears to make no difference to the likelihood of detecting adenomas in the colon or to the absolute number detected per colonoscopy. These results suggest that either polyp detection rate/number is not a robust measure of quality or the subjective measure of bowel preparation is not discriminatory. Further prospective studies are required to establish a validated bowel preparation score, which, if carefully structured, would standardise preparation as a quality measure and augment the factors known to influence polyp detection rate.

References 1. Valori R, Barton R. BSG Quality and Safety Indicators for Endoscopy. The Joint Advisory Group on GI Endoscopy. 2007.

2. Cairns SR, Scholefield JH, Steele RJ, et al. Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002). Gut 2010;59:666–90.

Competing interests None declared.