Introduction: Colorectal cancer (CRC) is the second leading cause of cancer-related deaths amongst men and women together in the United States. Screening colonoscopies have been proven to reduce CRC mortality. However, the efficacy of colonoscopies can be hindered by poor bowel preparation due to poor visualization and a higher likelihood of missing polyps and other colonic lesions including CRC. Per ASGE, adenoma detection rate (ADR) for combined male and female population is 25%. This retrospective study aims to identify the ADR for patients with inadequate bowel preparation noted during colonoscopies at our institution to emphasize the importance of quality bowel preparation.
Methods: During the years 2018-2020, a total of 250 inadequately prepared colonoscopies were examined at University of Louisville Hospital for our study. 28 colonoscopies were excluded due to being aborted prior to the procedure brown stool being present on exam. 14 colonoscopies did not have pathology reports and were also excluded. The study was a retrospective single-center cohort study reviewing risk factors in patients with inadequate bowel preparation noted during colonoscopy. A Boston Bowel Preparation Scale (BBPS) was used with score of < 6 (inadequate preparation) and ≥6 (adequate preparation).
Results: This study specifically examined the adenomatous detection rate for patients with poor colonoscopy preparation. Of these, 27 patients with screening colonoscopy indications had adenomatous or high-risk polyps with an ADR of 10.8%. This was well below the ASGE quality indicator for ADR for screening colonoscopies. 18 non-screening colonoscopies had an ADR of 7.2%. Additionally, there was a total of 91 the patients who came back for repeat colonoscopy within a 3-year time span after having poor bowel preparation or aborted procedure initially. 2 patients were missing pathology reports and excluded. 29 patients were found to have adenomatous or high-risk polyps for a total of 32.5% of patients with repeat colonoscopy who initially had poor bowel preparation or aborted procedure.
Discussion: Having a BBPS score of 5 or less considerably decreased ADR compared to ASGE standards. It is critically important that patients who have poor bowel prep return for repeat colonoscopy due to high risk of missing adenomatous or high-risk polyps as shown by the follow-up data. ADR is far below the endoscopist expectation without adequate bowel preparation in both screening and non-screening colonoscopies.
