Seasonal Variation of Colonoscopy Bowel Preparation

Abstract

Introduction: Little is known about the association between season of the year and bowel preparation quality for colonoscopy. We investigated whether season of the year is an independent factor for bowel preparation quality. Methods: We performed a retrospective study of 985 randomly selected patients (mean age 60.2±10.4; 94% male) who received outpatient colonoscopies in 2012 at the Veterans Affairs Medical Center in Oklahoma City, Oklahoma. 90% received conventional bowel preparation (4 liters of Golytely® the night before). Quality of bowel preparation was scored using the Boston Bowel Preparation Scale (BBPS) and categorized as either excellent vs. not excellent (BBPS≥7 vs. BBPS<7) or adequate vs. inadequate (BBPS≥5 vs. BBPS<5). A multivariate logistic regression analysis to identify factors independently associated with excellent bowel preparation was performed. Results: Bowel preparation quality was excellent in 39% of patients and adequate in 91%. There was no seasonal variation for adequate bowel preparation. However, there was a significant increase in excellent bowel preparation in the spring and summer compared to autumn and winter (Table 1). A similar trend of increased rate of excellent bowel preparation was observed in the subgroup of patients using split dose bowel preparation (Table 2). Independent factors for excellent bowel preparation were spring and summer scheduling (OR, 1.6; 95% CI, 1.2-2.1; p<0.0008), split bowel preparation (OR, 1.6; 95% CI, 1.0-2.4; p=0.03) and use of narcotics (OR, 0.7; 95% CI, 0.5-0.9; P=0.02).Table 1Table 2Conclusion: Spring and summer scheduled colonoscopies are associated with greater likelihood of achieving excellent bowel preparation. Seasonal variations in patient’s eating behavior, fluid consumption, exercise and circadian rhythm could alter colonic transit and hence, quality of bowel preparation for colonoscopy.