A practice-based trial of motivational interviewing and adherence in hypertensive African Americans

Background: Poor medication adherence is a significant problem in hypertensive African Americans. Although motivational interviewing (MINT) is effective for adoption and maintenance of health behaviors in patients with chronic diseases, its effect on medication adherence remains untested in this population. Methods: This randomized controlled trial tested the effect of a practice-based MINT counseling vs. usual care (UC) on medication adherence and blood pressure (BP) in 190 hypertensive African Americans (88% women; mean age 54 years). Patients were recruited from two community-based primary care practices in New York City. The primary outcome was adherence measured by electronic pill monitors; the secondary outcome was within-patient change in office BP from baseline to 12 months. Results: Baseline adherence was similar in both groups (56.2 and 56.6% for MINT and UC, respectively, P = 0.94). Based on intent-to-treat analysis using mixed-effects regression, a significant time x group interaction with model-predicted posttreatment adherence rates of 43 and 57% were found in the UC and MINT groups, respectively (P = 0.027), with a between-group difference of 14% (95% confidence interval, -0.2 to -27%). The between-group difference in systolic and diastolic BP was -6.1 mm Hg (P = 0.065) and -1.4 mm Hg (P = 0.465), respectively, in favor of the MINT group. Conclusions: A practice-based MINT counseling led to steady maintenance of medication adherence over time, compared to significant decline in adherence for UC patients. This effect was associated with a modest, nonsignificant trend toward a net reduction in systolic BP in favor of the MINT group.