Graphical education and appropriate time before elective colonoscopy make better bowel preparation.

Background: Inadequate bowel preparation leads to lower polyp detection rates, longer procedure times and lower cecal intubation rates. However, there is no consensus about high-quality bowel preparation, so our study evaluated graphical education and appropriate time before elective colonoscopy. Patients and Methods: We performed a secondary analysis of a national colorectal cancer screening programme of 738 patients. The patients were divided into a group given a graphical information manual (n = 242) or a word-only one (n = 496). They were also divided into groups according to the interval between bowel preparation and colonoscopy: 6-8 h (Group 1, n = 106), 9-12 h (Group 2, n = 228) and 13-17 h (Group 3, n = 402). All patients were scored according to the Boston Bowel Preparation Scale (BBPS) during the examination. Results: The bowel preparation of the graphical group was significantly better than the text group (P < 0.001). After adjustment, the bowel preparation score of Group 1 and Group 2 were both significantly higher than that of Group 3 (P = 0.012 and P = 0.032). Maximum BBPS was 6.31 when the interval time was 6.52 h (95% confidence interval: 5.95-6.66), and when the interval was <10 h, the BBPS was ≥6. Conclusion: High-quality bowel preparation was linked to graphical education and appropriate time before colonoscopy. We suggest that the interval between taking the first laxative and colonoscopy should be <10 h, preferably 6.5 h. Prospective multicentre research is needed to give more evidence of high-quality bowel preparation methods.