Risk Factors for Low Pharmacy Refill Adherence Among Older Hypertensive Men and Women by Race

Background: Sex-race stratification may lead to identification of risk factors for low antihypertensive medication adherence that are not apparent when assessing risk factors in women and men without race stratification. We examined risk factors associated with low pharmacy refill adherence across sex-race subgroups (white women, black women, white men, black men) within the Cohort Study of Medication Adherence among Older Adults (n = 2,122). Methods: Pharmacy refill adherence was calculated as proportion of days covered using all antihypertensive prescriptions filled in the year prior to a baseline risk factor survey. Sex- and sex-race-stratified multivariable Poisson regression models with robust standard errors were used to estimate adjusted prevalence ratios and 95% confidence intervals for associations between participant characteristics and low adherence. Results: Prevalence of low adherence was 22.9% vs. 40.7% in white vs. black women (P < 0.001) and 26.3% vs. 37.2% in white vs. black men (P = 0.003). In multivariable models, reducing antihypertensive medication due to cost was associated with low adherence within each sex-race subgroup. Additional factors associated with low adherence included shorter hypertension duration and comorbidities in white women; not being married and depressive symptoms in white men; and ≥6 primary care visits/year and complementary and alternative medicine use in black men. Among men, not being married and reporting depressive symptoms were associated with low adherence for whites, but not blacks. Conclusions: Identification of sex-race-specific risk factors for low antihypertensive medication adherence may guide development and implementation of tailored interventions to increase antihypertensive medication adherence and blood pressure control among older patients.