Is it time we split bowel preparation for all colonoscopies? Outcomes from a national survey of bowel preparation practice in the UK

Introduction: Adequate bowel preparation is a prerequisite for effective colonoscopy. Split bowel preparation results in optimal cleansing. This study assessed the bowel preparation regimes advised by endoscopy units across the UK, and correlated the differences with outcomes.

Methods: Trusts in the UK were surveyed, with data requested between January 2018 and January 2019, including: the type and timing of preparation, pre-endoscopy diet, adequacy rates and polyp detection. Trusts were grouped according to the timing of bowel preparation. χ2 test was used to assess for differences in bowel preparation adequacy.

Results: Moviprep was the first line bowel preparation in 79% of trusts. Only 7% of trusts advised splitting bowel preparation for all procedures, however, 91% used split bowel preparation for afternoon procedures. Trusts that split preparation for all procedures had an inadequacy rate of 6.7%, compared with 8.5% (p<0.001) for those that split preparation for PM procedures alone and 9.5% (p<0.001) for those that provided day before preparation for all procedures. Morning procedures with day-before preparation had a higher rate of inadequate cleansing than afternoon procedures that received split preparation (7.7% vs 6.5 %, p<0.001). The polyp detection rate for procedures with adequate preparation was 37.1%, compared with 26.4% for those that were inadequate.

Conclusion: Most trusts in the UK do not provide instructions optimising the timing of bowel preparation prior to colonoscopy. This correlated with an increased rate of inadequate cleansing. Splitting bowel preparation is likely to reduce the impacts of poor cleansing: missed lesions, repeat colonoscopies and significant costs.