Associations Between Health Literacy and Medication Self-Management Among Community Health Center Patients with Uncontrolled Hypertension

PURPOSE: Examine associations between health literacy and several medication self-management constructs among a population of adults with uncontrolled hypertension. PATIENTS AND METHODS: Cross-sectional study of health center patients from the Chicago area with uncontrolled hypertension enrolled between April 2012 and February 2015. Medication self-management constructs—applied to hypertension medications, chronic condition medications and all medications—included: 1) medication reconciliation, 2) knowledge of drug indications, 3) understanding instructions and dosing, and 4) self-reported adherence over 4 days (no missed doses). We determined associations between health literacy and self-management outcomes using multivariable generalized linear regression. RESULTS: There were 1460 patients who completed screening interviews; 62.9% enrolled and had complete baseline data collected, and were included in the analysis. Of 919 participants, 47.4% had likely limited (low), 33.2% possibly limited, and 19.4% likely adequate health literacy. Compared to participants with likely adequate health literacy, participants with low health literacy were less likely to have chronic medications reconciled (18.0% versus 29.6%, p=0.007), know indications for chronic medications (64.1% versus 83.1%, p<0.001), and demonstrate understanding of instructions and dosing (68.1% versus 82.9%, p=0.001). Self-reported adherence to hypertension medications was higher among the low health literacy group (65.6% versus 56.0%, p=0.010). In multivariable models, health literacy was strongly associated with knowledge of drug indications, and understanding of instructions and dosing. CONCLUSION: Low health literacy was associated with worse medication self-management in several domains. However, non-adherence was greatest in the most health literate in unadjusted analysis. Among a population of patients with uncontrolled hypertension, the drivers of poor control may vary by health literacy.