Background: Successful bowel preparation is important for safe, efficacious, cost-effective colonoscopy procedures; however, poor preparation is common.
Objective: We sought to determine whether there was an association between health literacy and comprehension of typical written instructions on how to prepare for a colonoscopy to enable more targeted interventions in this area.
Design: This is a cross-sectional observational study.
Setting: This study was performed at primary care clinics and federally qualified health centers in Chicago, Illinois.
Patients: Seven hundred sixty-four participants (mean age, 63 years; SD, 5.42) were recruited. The sample was from a mixed sociodemographic background, and 71.9% of the participants were classified as having adequate health literacy scores.
Intervention: Seven hundred sixty-four participants were presented with an information leaflet outlining the bowel preparatory instructions for colonoscopy.
Main outcome measures: Five questions were used to assess participants' comprehension of the instructions in an "open book" test.
Results: Comprehension scores on the bowel preparation items were low. The mean number of items correctly answered was 3.2 (SD, 1.2) of a possible 5. Comprehension scores overall and for each individual item differed significantly by health literacy level (all p < 0.001). After controlling for sex, age, race, socioeconomic status, and previous colonoscopy experience in a multivariable model, health literacy was a significant predictor of comprehension (inadequate vs adequate: β = -0.2; p < 0.001; marginal vs adequate: β = -0.2; p < 0.001).
Limitations: The outcome represents a simulated task and not actual comprehension of preparation instructions for participants' own recommended behavior.
Conclusions: Comprehension of a written colonoscopy preparation leaflet was generally low and significantly lower among people with low health literacy. Poor comprehension has implications for the safety and economic impact of gastroenterological procedures such as colonoscopy. Therefore, future interventions should aim to improve comprehension of complex medical information by reducing literacy-related barriers.