Video Capsule Endoscopy and Physical Activity: Increased Activity Correlates with Shorter Bowel Transit Times

Abstract

Introduction: Video capsule endoscopy (VCE) is the preferred modality for assessment of the small bowel mucosa, but it is limited by the battery lifespan of the device and reliance on bowel motility for propulsion. Lack of physical activity has been proposed as a potential cause of incomplete studies. The aim of this study was to prospectively investigate the association between physical activity and VCE completion and bowel transit times. Methods: All ambulatory outpatients undergoing VCE were assessed for inclusion. After consent, relevant clinical characteristics were obtained. At the time of ingestion of a VCE with standard 8 hour battery, a sealed pedometer was attached to the patient. At the conclusion of the procedure, the step-count was recorded. VCE completion was assessed by univariable and multivariable logistic regression models which included pedometer step count (500 steps as one unit). Total transit time was analyzed by univariable and multivariable Cox proportional hazards models. Gastric and small bowel transit times were assessed in univariable Cox proportional hazards models. The hazard ratios (HR) indicate the “hazard” of completion, such that hazard ratios greater than 1 indicate reduced transit time. Results: One hundred patients were included, with mean age 50.9 years and 64% female. VCE was completed in 93 patients (93%). The mean step count was 3,125 steps (SD = 2,070). Pedometer step count was significantly associated with shorter total transit times (HR = 1.08; 95% CI 1.02, 1.14), gastric transit times (HR = 1.06; 95% CI 1.01, 1.11) and small bowel transit times (HR = 1.06; 1.01, 1.12) in univariable analysis. Step counts remained significantly associated with total transit times in the multivariable model (HR = 1.09; 95% CI 1.03, 1.16; Table 1). In univariable and multivariable analysis, step count was not significantly associated with VCE completion (p = 0.17 and 0.15 respectively; Table 2).Table 1: Multivariable Cox proportional hazards model for video capsule endoscopy total transit timeTable 2: Multivariable logistic regression for video capsule endoscopy completionConclusion: In the first study to use a validated tool to directly measure physical activity, higher step counts during outpatient VCE correlated with shorter bowel transit times but were not significantly associated with study completion. We suspect the decrease in bowel transit times did not translate into higher rates of study completion due to the high baseline completion rate. Given the lack of negative side effects, we recommend encouraging physical activity during VCE studies.