Background: To prepare for colonoscopy, patients must consume a bowel purgative and travel from their home to the site of their procedure. The timing of bowel purgative ingestion predicts bowel preparation quality. Currently, it is not known if driving distance impacts bowel preparation quality or adenoma detection.
Objective: This study investigates the effect of driving distance on bowel preparation and adenoma detection.
Design: This is a cross-sectional retrospective analysis of outpatient screening colonoscopy procedures that were completed at an academic medical center.
Participants: A total of 5089 patients who completed screening colonoscopy across 3 procedure units were analyzed.
Main measures: Description of bowel preparation was dichotomized to either adequate or inadequate. Patient residential addresses were converted into geographic coordinates for geospatial analysis of driving distance to their colonoscopy site.
Key results: Median driving distance was 13.1 miles. Eighty-nine percent of patients had an adequate bowel preparation. The rate of adenoma detection was 37%. On multivariable logistic regression adjusting for age, sex, race, insurance, endoscopist, and site, increasing driving distance (10-mile increments) was negatively associated with adequate bowel preparation (odds ratio = 0.91; 95% confidence interval 0.85 to 0.97), while adenoma detection was positively associated with adequate bowel preparation (odds ratio = 1.53; 95% confidence interval 1.24 to 1.88) but not with driving distance (odds ratio = 1.02; 95% confidence interval 0.98 to 1.06). Driving distances of 30 miles or less were associated with adequate bowel preparation (odds ratio = 1.37; 95% confidence interval 1.09 to 1.72).
Conclusions: Increasing driving distance to screening colonoscopy was negatively associated with adequate bowel preparation but not adenoma detection. Among an academic medical center population, the likelihood of adequate bowel preparation was highest in patients traveling 30 miles or less to their screening colonoscopy. Patient driving distance to colonoscopy is an important consideration in optimizing screening colonoscopy quality.
Keywords: colonoscopy; quality assurance; screening; travel time.