Prospective study of factors important to achieve observation of the entire colon on colon capsule endoscopy

Background: Colon capsule endoscopy (CCE) is a procedure in which capsule swallowing facilitates observation of the lumen of the entire digestive tract. It does not require an air supply, and is a noninvasive procedure with a markedly low risk of adverse events in comparison with conventional colonoscopy (CS). It reduces patient stress, and may be acceptable to patients. A limitation of this procedure is that the entire colon observation rate (CCE excretion rate, completed CCE rate) is not 100%. In this study, we prospectively investigated clinical factors important to achieve observation of the entire colon on CCE. Methods:The participants were 70 patients for whom CCE was scheduled, and from whom written informed consent regarding participation in this study was obtained. We selected patient background/examination factors, and analyzed all factors involved in observation of the entire colon and factors for completion of the CCE within 4 h after the start of examination using multivariate analysis. Results: Of the 70 enrolled patients, 64 were analyzed, excluding 6. On multiple logistic analysis, only a water intake of 12.0 ml/min during examination [p = 0.025, odds ratio (OR): 46.753, 95% confidence interval (CI): 1.630-1341.248] was identified as an independent predictive factor involved in observation of the entire colon. With respect to factors involved in the completion of CCE within 4 h, multiple logistic analysis showed that a body mass index (BMI) of 25 (p = 0.039, OR: 13.723, 95% CI: 1.135-165.913), the absence of constipation (p = 0.030, OR: 13.988, 95% CI: 1.287-152.047), and a water intake of 12.0 ml/min during examination (p = 0.004, OR: 12.028, 95% CI: 2.225-65.029) were independent predictive factors. Conclusions: Completion of a CCE was most closely related to water intake per hour. In addition to water intake, CCE-promoting factors included a high BMI and the absence of constipation.