The quality of colon cleansing is a major determinant of quality of colonoscopy. To
our knowledge, the impact of bowel preparation on the quality of colonoscopy has not
been assessed prospectively in a large multicenter study. Therefore, this study assessed
the factors that determine colon-cleansing quality and the impact of cleansing quality
on the technical performance and diagnostic yield of colonoscopy.
Twenty-one centers from 11 countries participated in this prospective observational
study. Colon-cleansing quality was assessed on a 5-point scale and was categorized
on 3 levels. The clinical indication for colonoscopy, diagnoses, and technical parameters
related to colonoscopy were recorded.
A total of 5832 patients were included in the study (48.7% men, mean age 57.6 [15.9]
years). Cleansing quality was lower in elderly patients and in patients in the hospital.
Procedures in poorly prepared patients were longer, more difficult, and more often
incomplete. The detection of polyps of any size depended on cleansing quality: odds
ratio (OR) 1.73: 95% confidence interval (CI)[1.28, 2.36] for intermediate-quality
compared with low-quality preparation; and OR 1.46: 95% CI[1.11, 1.93] for high-quality
compared with low-quality preparation. For polyps >10 mm in size, corresponding ORs
were 1.0 for low-quality cleansing, OR 1.83: 95% CI[1.11, 3.05] for intermediate-quality
cleansing, and OR 1.72: 95% CI[1.11, 2.67] for high-quality cleansing. Cancers were
not detected less frequently in the case of poor preparation.
Cleansing quality critically determines quality, difficulty, speed, and completeness
of colonoscopy, and is lower in hospitalized patients and patients with higher levels
of comorbid conditions. The proportion of patients who undergo polypectomy increases
with higher cleansing quality, whereas colon cancer detection does not seem to critically
depend on the quality of bowel preparation.