Comparison of In-Hospital and At-Home Administration of Bowel Preparation Agents Before Outpatient Colonoscopy in...

Most patients take bowel preparation agents at home before undergoing outpatient colonoscopy. However, some elderly patients undergo bowel preparation at the hospital. This study compared the outcomes of in-hospital (Group A) versus at-home (Group B) bowel preparation in elderly patients to clarify the usefulness of in-hospital bowel preparation.

From September 2022 to September 2023, 151 patients aged 70 years or older undergoing outpatient colonoscopy at Ureshino Medical Center were prospectively enrolled (51 in Group A and 100 in Group B). The primary endpoint was bowel preparation time. Secondary endpoints were the number of defecations, colonoscopy start time, and adverse events. Propensity score matching (PSM) was applied to account for baseline differences, and multivariate analysis was conducted to identify factors associated with bowel preparation time.

After PSM, 26 matched pairs were analyzed. Group A had a significantly shorter bowel preparation time (192.1 ± 80.5 vs. 271.1 ± 57.9 min, p < 0.001), shorter time from preparation to colonoscopy (259.3 ± 70.2 vs. 341.4 ± 67.1 min, p < 0.001), and fewer defecations (8.5 ± 4.6 vs. 11.2 ± 4.1, p < 0.001) than Group B. There were no significant intergroup differences in adverse events or patient satisfaction. Multivariate analysis revealed that in-hospital preparation was strongly associated with shorter bowel preparation time (odds ratio 8.87, 95% CI 3.16-24.92, p < 0.001).

For elderly patients, in-hospital bowel preparation is beneficial because it significantly shortens preparation and colonoscopy start times and reduces defecations, while maintaining safety and satisfaction rates compared with at-home preparation. Trial Registration: University Hospital Medical Information Network Clinical Trials Registry: UMIN000057045.