Risk factors for inadequate colonoscopy bowel preparations in African Americans and whites at an urban medical center.

OBJECTIVES: Poor bowel preparation leads to inadequate examinations and shorter surveillance intervals for colorectal cancer screening. Previous studies regarding risk factors for inadequate preparation have not included large numbers of African Americans. Our aim was to determine the prevalence of inadequate bowel preparation on initial and follow-up colonoscopy in a large, racially diverse patient population.
METHODS: Colonoscopies performed during a 1-year period were analyzed retrospectively. Factors including age, sex, race, and start time were recorded. Patient ZIP codes were linked to census data to estimate education and income. For examinations with inadequate bowel preparations, we collected data on recommendations and the preparation quality of follow-up procedures.
RESULTS: We included 3741 patients (40.2% African American). Of these, 66.9% had adequate bowel preparation and 33.1% had inadequate bowel preparation. African Americans had the highest prevalence of inadequate preparations at 43.0%. African American race was a predictor of inadequate bowel preparation, despite controlling for education and income. Age, male sex, and procedure taking place after 12 pm also were risk factors for inadequate preparation. Receipt of specific preparation instructions on the endoscopy report did not affect preparation quality on follow-up examination. Our study found a high rate (33.1%) of inadequate bowel preparations, and African American race was found to be an independent risk factor for inadequate preparation. We validated previously reported risk factors including age, male sex, and later procedure time. Finally, we noted high rates of inadequate preparation on follow-up examinations.
CONCLUSIONS: Improving the quality of colonoscopy bowel preparation is important for colorectal cancer prevention, especially in high-risk populations such as African Americans.