SAN DIEGO – .
Of patients whose colonoscopies were performed the day after a holiday, 55.4% had inadequate bowel preparation, compared with 45.7% of those receiving colonoscopies on other days, for an odds ratio of 1.5 for inadequate preparation on the day after a holiday (95% confidence interval, 1.1-1.9; P = .006).
In addition to the lead finding, inadequate bowel prep was also more likely in the afternoon, and earlier in the week (OR, 1.6 and 1.3, respectively), said Ammar Nassri, MD, a gastroenterology fellow at the University of Florida, Jacksonville.
Patients who were male and white were more likely to have inadequate bowel preparation (OR, 1.3 and 2.7, respectively). Having Medicaid as opposed to other forms of insurance also upped the likelihood of inadequate bowel preparation (OR, 1.9).
It’s important to identify modifiable factors associated with inadequate bowel preparation for a number of reasons. Among them, said Dr. Nassri, is cost-effectiveness: Screening colonoscopy has been found to be cost effective, compared with fecal immunochemical testing only when the inadequate bowel prep rate is 13% or less.
Adenomas are more likely to be missed with inadequate bowel preparation as well, he noted, with one study finding missed adenomas on 33% of subsequent colonoscopies performed after an initial colonoscopy with inadequate preparation.
Also, inadequate preparation can mean longer procedures and increased likelihood of failed procedures – and higher costs, he said.
“Several studies have created prediction models to predict the likelihood of having an inadequate bowel preparation, but these models have not gained widespread acceptance,” said Dr. Nassri.
He and his collaborators aimed to identify the rate of inadequate bowel preparation in their patient population, and to examine the association of modifiable variables with adequacy of preparation. These included the day of the week, the time of day, and whether a colonoscopy followed a holiday.
Additionally, the investigators looked at various patient demographic variables to see whether they were associated with adequacy of bowel preparation. Adult patients who received outpatient colonoscopy over a 3-year period were included. Preparation was considered adequate if it was assigned a score of at least 6 on the Boston Bowel Preparation Scale, or at least “fair” on the Aronchik scale.
A total of 6,510 patients were included. The mean age was 56.3 years, and about 60% were female. Just over half (51.3%) were African American; 46.6% were white. Over half of patients (56.4%) had health insurance provided by city contract or Florida Medicaid; the remainder had either Medicare or commercial insurance.
Overall, nearly half of patients (46%) had inadequate bowel preparation. Half of males overall had adequate bowel preparation, compared with 57% of females (P less than .001). As the hour of the colonoscopy grew later, the likelihood of adequacy of bowel preparation dropped. The inverse relationship was statistically significant (P less than .001), with over 60% of 7 a.m. colonoscopies having adequate preparation. By 3 p.m., over 60% of bowel preparations were inadequate in the University of Florida cohort.
Colonoscopies performed later in the week were most likely to have adequate bowel preparation, with rates nearing 60% by Friday, compared with rates just over or at 50% for the first 3 days of the week (P less than .001).
“This study showed that a colonoscopy on the day after a holiday has a higher rate of inadequate bowel preparation,” said Dr. Nassri. Conversely, he said, “Colonoscopy toward the end of the week has a higher likelihood of adequate bowel preparation.”
The present work, he said, “re-demonstrated that procedures done later in the day have a poorer bowel preparation.”
Dr. Nassri reported no conflicts of interest.