Split-dose bowel preparation improves adequacy of bowel preparation and gastroenterologists' adherence to National Colorectal Cancer Screening and Surveillance Guidelines.

Aim: To quantify the impact of split-dose regimen on endoscopists' compliance with guideline recommendations for timing of repeat colonoscopy in patients with normal colonoscopy or 1-2 small polyps (< 10 mm).

Methods: A retrospective chart review of all endoscopy reports was undertaken in average-risk individuals > 50 years old with a normal screening colonoscopy and 1-2 small polyps. Data were abstracted from two time periods, pre and post-split-dose bowel preparation institution. Main outcome measurements were recommendation for timing of repeat colonoscopy and bowel preparation quality. Bivariate analysis by tests and Student's -tests were performed to assess differences between the two cohorts. Multivariable logistic regression was used with guideline consistent recommendations as the dependent variables and an indicator for 2011 cohort as the primary predictor.

Results: Four thousand two hundred and twenty-five patients were included in the study; 47.0% (1987) prior to the institution of split dose bowel preparation, and 53.0% (2238) after the institution of split dose bowel preparation. Overall, 82.2% ( = 3472) of the colonoscopies were compliant with guideline recommendations, with a small but significantly increased compliance rate in year 2011 (83.7%) compared to year 2009 (80.4%, = 0.005), corresponding to an unadjusted odds ratio of 1.25 (95%CI: 1.07-1.47; = 0.005). Colonoscopies with either "Adequate" or "Excellent" had increased from 30.6% in year 2009 to 39.6% in year 2011 ( < 0.001). However, there was no significant difference in poor/inadequate category of bowel preparation as there was a mild increase from 4.6% in year 2009 to 5.1% in year 2011 ( = 0.50).

Conclusion: Split-dose bowel regimen increases endoscopists' compliance to guidelines in average-risk patients with normal colonoscopy or 1-2 small polyps.