Objective: To determine whether literacy mediates the association between education, hypertension knowledge and control.
Methods: In-person interviews with a literacy assessment and chart review were conducted with 330 hypertensive patients from six primary care safety net clinics. Mediational analysis was used to test the role of literacy skills in explaining the relationship between education and hypertension knowledge and control.
Results: In multivariate analyses that did not make an adjustment for the other variable, both lower educational attainment and more limited literacy were found to be significant independent predictors of poorer hypertension knowledge and control. When literacy was entered into models that included education only, the association between education and knowledge was fully attenuated and no longer significant (Grades 1-8: beta=-0.30, 95% CI=-1.44-0.83), while the relationship between education and blood pressure control was only minimally reduced (AOR 2.46, 95% CI 2.10-2.88). More limited literacy skills also was associated with hypertension control in the final model (AOR 2.68, 95% CI 1.54-4.70).
Conclusion: Patient literacy mediated the relationship between education and hypertension knowledge. Literacy was a significant independent predictor of blood pressure control, but only minimally explained the relationship between education and blood pressure.
Practice implications: Health literacy is critical to the design of educational tools to improve knowledge acquisition. However, in order to impact health outcome, future health literacy studies should also address other psychosocial factors that impact motivation and capability to manage disease.