Multicenter feasibility study of bowel preparation with castor oil for colon capsule endoscopy

Background and Aim: Extensive use of laxatives and incomplete excretion rates are problematic for colon capsule endoscopy (CCE). The aim of the present study was to determine the effectiveness of castor oil as a booster. Methods: At four Japanese hospitals, 319 examinees undergoing CCE were enrolled retrospectively. Before and after the introduction of castor oil, other preparation reagents were unchanged. Results: Of 319 examinees who underwent CCE, 152 and 167 examinees took regimens with castor oil (between November 2013 and June 2016) and without castor oil (between October 2015 and September 2017), respectively. Capsule excretion rates within its battery life in the groups with and without castor oil were 97% and 81%, respectively (P < 0.0001). Multivariate analysis showed that ages younger than 65 years (adjusted odds ratio [OR], 3.00; P = 0.0048), male gender (adjusted OR, 3.20; P = 0.0051), and use of castor oil (adjusted OR, 6.29; P = 0.0003) were predictors of capsule excretion within its battery life. Small bowel transit time was shorter and total volume of lavage and fluid intake was lower with castor oil than without (P = 0.0154 and 0.0013, respectively). Overall adequate cleansing level ratios with and without castor oil were 74% and 83%, respectively (P = 0.0713). Per-examinee sensitivity for polyps ≥6 mm with and without castor oil was 83% and 85%, respectively, with specificities of 80% and 78%, respectively. Conclusion: Bowel preparation with castor oil was effective for improving capsule excretion rate and reducing liquid loading.