Low Health Literacy is Associated with Less Knowledge about Colorectal Cancer but Not Adherence to Colonoscopy among Veterans

Purpose: Low literacy is an important predictor of health behavior and has been shown to have an impact on adherence to medications and recommendations to undergo cancer screening. Our objective was to determine the association between health literacy, knowledge and adherence to colonoscopy among veterans at high risk for colorectal cancer (CRC). Methods: In this prospective, observational cohort study, subjects referred for diagnostic evaluation of heme-positive stool, hematochezia, anemia, or a family history of CRC, were recruited from the Durham VA Gastroenterology Clinic. Subjects completed a validated CRC knowledge questionnaire (total knowledge score ranged from 0–100) and were administered the Rapid Estimate of Adult Literacy in Medicine (REALM). The REALM was used to classify individuals as having adequate (>9th grade) or low (<8th grade) health literacy (LHL). The primary endpoint was adherence to colonoscopy, defined as an individual having undergone a complete colonoscopy. Chi-square statistic and T-test were used to evaluate differences between groups. Results: A total of 619 subjects completed the study. Mean age was 59 years and 91% were male; 53% were White, 42% Black; 44% of subjects had LHL. Total knowledge score was slightly lower in the LHL group (76% vs. 80%; P= 0.02). Overall adherence rate was high: 518 (84%) completed their diagnostic colonoscopy. Adherence status between the 2 groups was lower in the LHL group but this difference was not statistically significant (82% versus 86%, P= 0.24). Conclusion: LHL is associated with less knowledge about CRC screening but this is the only study to date that has looked at the impact of health literacy on outcomes such as adherence to diagnostic colonoscopy. While LHL rates were high in this cohort of veterans, and this may have translated into less knowledge about CRC, importantly, it did not have an impact on adherence to diagnostic colonoscopy. These findings are especially significant since adherence to colonoscopic evaluation is imperative in this patient population referred for diagnostic evaluation.