Health System Factors and Antihypertensive Adherence in a Racially and Ethnically Diverse Cohort of New Users

Background: The purpose of this study was to identify potential health system solutions to suboptimal use of antihypertensive therapy in a diverse cohort of patients initiating treatment. Methods: Using a hypertension registry at Kaiser Permanente Northern California, we conducted a retrospective cohort study of 44 167 adults (age, >= 18 years) with hypertension who were new users of antihypertensive therapy in 2008. We used multivariate logistic regression analysis to model the relationships between race/ethnicity, specific health system factors, and early non-persistence (failing to refill the first prescription within 90 days) and nonadherence (<80% of days covered during the 12 months following the start of treatment), respectively, controlling for sociodemographic and clinical risk factors. Results: More than 30% of patients were early nonpersistent and 1 in 5 were nonadherent to therapy. Nonwhites were more likely to exhibit both types of suboptimal medication-taking behavior compared with whites. In logistic regression models adjusted for sociodemographic, clinical, and health system factors, nonwhite race was associated with early nonpersistence (black: odds ratio, 1.56 [95% CI, 1.43-1.70]; Asian: 1.40 [1.29-1.51]; Hispanic: 1.46 [1.35-1.57]) and nonadherence (black: 1.55 [1.37-1.77]; Asian: 1.13 [1.00-1.28]; Hispanic: 1.46 [1.31-1.63]). The likelihood of early nonpersistence varied between Asians and Hispanics by choice of first-line therapy. In addition, racial and ethnic differences in nonadherence were appreciably attenuated when medication co-payment and mail-order pharmacy use were accounted for in the models. Conclusions: Racial/ethnic differences in medication-taking behavior occur early in the course of treatment. However, health system strategies designed to reduce patient co-payments, ease access to medications, and optimize the choice of initial therapy may be effective tools in narrowing persistent gaps in the use of these and other clinically effective therapies. JAMA Intern Med. 2013;173(1):54-61. Published online December 10, 2012. doi:10.1001/2013.jamainternmed.955