Impact of Health Literacy on Medication Adherence Among Black Medicaid Beneficiaries with Hypertension in Delaware: A Cross-Sectional Study

Racial and ethnic minorities are disproportionately affected by limited health literacy. Therefore, this study assessed census block health literacy level and medication adherence in Delaware among Black individuals with hypertension (HTN) receiving health care through Medicaid. This was a cross-sectional study of Black Delaware Medicaid beneficiaries (18-64 years old) from the 3 counties in Delaware (Kent, New Castle, and Sussex) from 2016 to 2019. The primary outcome was medication adherence (full adherence = 80%-100%, partial adherence = 50%-79%, and nonadherence = 0-49%) as a function of health literacy. Health literacy scores were categorized as below basic (0-184), basic (184-225), intermediate (226-309), and proficient (310-500). The results of the study showed that 18,958 participants (29%) had >= 1 HTN diagnosis during the study period. Mean area health literacy score for participants without HTN was significantly higher than participants with HTN (234.9 vs. 233.7, P < 0.0001). Men had lower odds of adherence compared with women (odds ratio [OR]: 0.83, 95% confidence interval [CI]: 0.75-0.92, P < 0.001). Increased time enrolled in Medicaid decreased full adherence. Participants 21-30 and 31-50 years of age are significantly less likely to have full adherence in comparison with participants 51-64 years of age (P < 0.0001). Participants living in an area with basic level of health literacy reported lower medication adherence than those living in an area with an intermediate level of health literacy (OR: 0.72, 95% CI: 0.64-0.81, P < 0.001). In conclusion, men, younger adults, increased time enrolled in Medicaid for the study period, and basic health literacy were significantly associated with low adherence to medication among 3 census blocks in Delaware.