Racial differences in blood pressure control: potential explanatory factors.

PURPOSE: Poor blood pressure control remains a common problem that contributes to significant cardiovascular morbidity and mortality, particularly among African Americans. We explored antihypertensive medication adherence and other factors that may explain racial differences in blood pressure control.

METHODS: Baseline data were obtained from the Veteran's Study to Improve The Control of Hypertension, a randomized controlled trial designed to improve blood pressure control. Clinical, demographic, and psychosocial factors relating to blood pressure control were examined.

RESULTS: A total of 569 patients who were African American (41%) or white (59%) were enrolled in the study. African Americans were more likely to have inadequate baseline blood pressure control than whites (63% vs 50%; odds ratio = 1.70; 95% confidence interval [CI] 1.20-2.41). Among 20 factors related to blood pressure control, African Americans also had a higher odds ratio of being nonadherent to their medication, being more functionally illiterate, and having a family member with hypertension compared with whites. Compared with whites, African Americans also were more likely to perceive high blood pressure as serious and to experience the side effect of increased urination compared with whites. Adjusting for these differences reduced the odds ratio of African Americans having adequate blood pressure control to 1.59 (95% confidence interval 1.09-2.29).

CONCLUSIONS: In this sample of hypertensive patients who have good access to health care and medication benefits, African Americans continued to have lower levels of blood pressure control despite considering more than 20 factors related to blood pressure control. Interventions designed to improve medication adherence need to take race into account. Patients' self-reports of failure to take medications provide an opportunity for clinicians to explore reasons for medication nonadherence, thereby improving adherence and potentially blood pressure control.