Comparison of Bowel Preparation Quality for Colonoscopy in Inpatients Versus Outpatients: A Single-Center Prospective Observational Study in Lebanon

Aims To compare the adequacy of bowel preparation between inpatients and outpatients and to identify independent predictors of poor bowel cleansing. Methods This prospective, single-center observational study was conducted at a tertiary care hospital and included colonoscopies performed on both inpatients and outpatients. A total of 217 procedures were analyzed (109 outpatients and 108 inpatients). Bowel preparation quality was evaluated using the Boston Bowel Preparation Scale (BBPS). Univariate and multivariate logistic regression analyses were used to identify factors associated with inadequate bowel preparation [ 1 ] [ 2 ] [ 3 ] [ 4 ] [ 5 ] [ 6 ] [ 7 ] [ 8 ] [ 9 ] [ 10 ] [ 11 ] [ 12 ] [ 13 ] [ 14 ] [ 15 ] [ 16 ] [ 17 ] [ 18 ] [ 19 ] [ 20 ] [ 21 ] [ 22 ] [ 23 ] [ 24 ] [ 25 ]. Results No statistically significant difference in bowel preparation adequacy was found between inpatients and outpatients. In the overall cohort, two independent predictors of bowel preparation quality were identified. Smoking was significantly associated with inadequate cleansing, with smokers having 62.4% lower odds of achieving good preparation compared to non-smokers (OR=0.376; p=0.002). Conversely, the use of a split-dose regimen significantly improved bowel cleansing, increasing the odds of adequate preparation by nearly five times compared to single-dose regimens (OR=4.96; p=0.001). Conclusions Inpatient status was not associated with inferior bowel preparation compared to outpatient status. Smoking and the type of bowel preparation regimen (split- vs. single-dose) were the most significant predictors of bowel cleansing quality. Publication History Article published online: 05 June 2026 © 2026. European Society of Gastrointestinal Endoscopy. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany