What Level of Bowel Prep Quality Requires Early Repeat Colonoscopy: Systematic Review and Meta-Analysis of the Impact of Preparation Quality on Adenoma Detection Rate

Abstract

OBJECTIVES Current guidelines recommend early repeat colonoscopy when bowel preparation quality is inadequate, defined as inability to detect polyps > 5 mm, but no data link specific bowel preparation categories or scores to this definition. Nevertheless, most physicians use a shortened screening/surveillance interval in patients with intermediate-quality preparation. We determined whether different levels of bowel preparation quality are associated with differences in adenoma detection rates (ADRs: proportion of colonoscopies with ≥1 adenoma) to help guide decisions regarding early repeat colonoscopy—with primary focus on intermediate-quality preparation. METHODS MEDLINE and Embase were searched for studies with adenoma or polyp detection rate stratified by bowel preparation quality. Preparation quality definitions were standardized on the basis of Aronchick definitions (excellent/good/fair/poor/insufficient), and primary analyses of ADR trichotomized bowel preparation quality: high quality (excellent/good), intermediate quality (fair), and low quality (poor/insufficient). Dichotomized analyses of adequate (excellent/good/fair) vs. inadequate (poor/insufficient) were also performed. RESULTS Eleven studies met the inclusion criteria. The primary analysis, ADR with intermediate- vs. high-quality preparation, showed an odds ratio (OR) of 0.94 (0.80–1.10) and absolute risk difference of −1% (−3%, 2%). ADRs were significantly higher with both intermediate-quality and high-quality preparation vs. low-quality preparation: OR = 1.39 (1.08–1.79) and 1.41 (1.21–1.64), with absolute risk increases of 5% for both. ADR and advanced ADR were significantly higher with adequate vs. inadequate preparation: OR = 1.30 (1.19–1.42) and 1.30 (1.02–1.67). Studies did not report other relevant outcomes such as total adenomas per colonoscopy. CONCLUSIONS ADR is not significantly different with intermediate-quality vs. high-quality bowel preparation. Our results confirm the need for early repeat colonoscopy with low-quality bowel preparation, but suggest that patients with intermediate/fair preparation quality may be followed up at standard guideline-recommended surveillance intervals without significantly affecting quality as measured by ADR.

Impact of gum chewing on the quality of bowel preparation for colonoscopy: an endoscopist-blinded, randomized controlled trial

“…Inadequate bowel preparation is associated with missed lesions, repeated colonoscopy, and higher adverse event rate (12,13). Various methods have been proposed to improve the quality of bowel preparation (14-16), nonetheless, suboptimal bowel preparation is still commonly encountered in clinical practice.…”

The clinical effectiveness of different surveillance strategies to prevent colorectal cancer in people with intermediate-grade colorectal adenomas: a retrospective cohort analysis, and psychological and economic evaluations

“…There is only weak evidence on how to salvage a procedure when bowel preparation is found to be inadequate. 61 However, the importance of achieving good bowel preparation cannot be overstated; a systematic review 62 found that adenoma detection rates were significantly higher in patients with adequate or good-quality preparation compared with poor-quality preparation.…”

Advances in Bowel Preparation for Colonoscopy

“…8 A recent systematic review and meta-analysis of 11 studies observed no difference in adenoma detection rate (ADR) between examinations with intermediate-quality (fair) compared with those with high-quality preparation (good or excellent) (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.80, 1.10). 9 In contrast, ADRs were significantly higher with both intermediate-quality (OR, 1.39; 95% CI, 1.08, 1.79) and high-quality preparations (OR, 1.41; 95% CI, 1.21, 1.64) compared with low-quality (poor) preparations. Similar findings were observed in an analysis of 13,000 colonoscopies within a statewide registry, with comparable ADRs in examinations with fair-quality versus optimalquality preparation.…”