Patient‐related factors related to prolonged preparation‐to‐colonoscopy interval and insufficient purgative intake before colonoscopy: A post‐hoc observational study

Objectives Prolonged preparation‐to‐colonoscopy (PC) interval and insufficient purgative intake (PI) are two important indicators for quality of bowel preparation for colonoscopy. We aimed to investigate patient‐related factors associated with increased PC interval or insufficient PI. Methods The post‐hoc regression analyses were performed using the data from two prospective studies (NCT04434625 and NCT04101097). Patients receiving reinforced instructions for bowel preparation were recruited. The co‐primary outcomes included prolonged PC interval or insufficient PI. Results Altogether 1806 patients from five endoscopic centers underwent bowel preparation from September 2019 to March 2021. The cut‐off values were 6 h for PC interval and 80% for PI. In all, 116 (6.4%) and 73 (4.0%) presented an extended PC interval and insufficient PI, respectively. Multivariate logistic regression analysis showed that a low education level was significantly associated with PC interval ≥6 h. Female sex, body mass index (BMI), and coronary artery disease (CAD) were found to be significantly correlated with insufficient PI in univariate analysis, while multivariate analysis demonstrated BMI <20 kg/m 2 (odds ratio [OR] 4.14, 95% confidence interval [CI] 1.92–8.94, P < 0.001) and 20–25 kg/m 2 (OR 2.23, 95% CI 1.33–3.73, P = 0.002) and CAD (OR 3.23, 95% CI 1.22–8.53, P = 0.018) were identified as independent risk factors for PI <80%. Conclusions In spite of reinforced education, a number of patients did not follow the instructions for bowel preparation. The factors for a prolonged PC interval did not overlap with those for insufficient PI. Individualized interference may be considered in different subpopulations.