Is Cognitive Impairment Associated with Inadequate Bowel Preparation for Colonoscopy?

Inadequate bowel preparation (IBP) for colonoscopies is associated with missed polyps and cancers, prolonged procedure times, lower colonoscopy completion rates, and need for a repeat procedure. The purposes of this study were to assess: 1) whether impaired cognitive status (measured by an abnormal clock drawing test) was associated with IBP, and 2) the association of participant demographic and clinical characteristics with IBP.

Cross-sectional cohort study conducted in 3 academic centers. Subjects, 50 to 85 years old, completed 5 stool tests on a single sample and a clock drawing before undergoing a screening or surveillance colonoscopy. Clock drawings were validated by the Mendes-Santos method and Watson method. A generalized linear mixed model was conducted to estimate factors associated with IBP, based on Aronchick bowel preparation score.

The 2,016 participants had a mean age of 63 years (SD = 7.95); 1,274 (63%) were female; 119 (6%) had IBP; and 421 (21%) had an abnormal clock drawing. After controlling for age in the multivariable model, the odds of having an IBP versus adequate were 1.44 (95% CI, 0.94-2.22) for those with an abnormal clock drawing score compared with those with a normal score. The only variable significantly associated with IBP was household income, with an odds of 2.48 (95% CI, 1.56-3.95) for household income of <$40,000 compared with income >$80,000.

Lower household income was associated with greater odds of IBP. The association between an abnormal clock drawing score and IBP was not statistically significant.NCT03264898 (clinicaltrials.gov) - Comparative Effectiveness of FITs with Colonoscopy.