Optimizing bowel preparation for colonoscopy: what are the predictors of an inadequate preparation?

This retrospective study evaluates factors that are associated with an inadequate bowel preparation.

A chart review was performed on 2,101 patients who underwent colonoscopy. The quality of preparation was classified as adequate or inadequate. Univariate and multivariate regression analyses identified factors associated with inadequate preparations.

A total of 91.5% of preparations were adequate. Standard preparations using polyethylene glycol-electrolyte solution and sodium picosulfate alone were 91.1% adequate. Regimens with adjuncts were 91.9% adequate. Factors that predicted an inadequate preparation include the following: stroke/dementia (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.6 to 7.7, P = .002), opioids (OR 2.3, 95% CI 1.1 to 4.6, P = .02), male sex (OR 2.0, 95% CI 1.4 to 2.9, P = .000), calcium channel blockers (OR 1.9, 95% CI 1.1 to 3.3, P = .03), and antidepressants (OR 1.7, 95% CI 1.1 to 2.7, P = .02).

Several factors are associated with inadequate preparations. Adjuncts do not improve preparation quality. The effect of patient education on preparation quality is an area for further research.