Split-Dose Bowel Preparation Reduces the Need for Early Repeat Colonoscopy Without Improving Adenoma Detection Rate

Split-dose bowel preparation is associated with improved mucosal visualization and patient tolerance, becoming a standard of care. However, quality measures data associated with this preparation are limited. At our academic tertiary-care facility, we aim to study the effect of changing from single- to split-dose preparation on colonoscopy quality measures. A retrospective cohort study with quality indicators was conducted using electronic medical record data. Cases were identified via ICD9 code V76.51, "Special screening for malignant neoplasms of colon." Single-dose preparation data was collected from 9/1/13 to 8/31/14. Split-dose preparation was implemented 11/2014, and data were collected from 1/1/15 to 8/31/15. A total of 1602 colonoscopies in the single-dose group and 1061 colonoscopies in the split-dose group were analyzed. The Boston Bowel Preparation Scale was significantly improved in the split-dose group 8.64 +/- SD 1.25 versus 8.25 +/- SD 1.61, p < 0.001. There was no significant difference in adenoma detection rate 40.7% (95% CI 37.8-43.7%) versus 40.5% (95% CI 38.1-42.9%), p = 0.92; however, the rate for recommending an early repeat examination due to an inadequate bowel preparation was significantly decreased to 3.9% (95% CI 2.7-5.0%) versus 8.9% (95% CI 1.52-2.97%), p < 0.001. While split-dose preparation significantly improves overall bowel cleanliness, there is no significant adenoma detection rate improvement with high baseline rate, suggesting a threshold which may not improve with enhanced preparations. Split-dose preparation significantly reduces the frequency with which inadequate preparation prompts an early repeat examination, which has important clinical implications on performance, costs, and patient experience, providing further evidence supporting split-dose preparation use.