Background Medication nonadherence contributes to poor health outcomes but remains challenging to identify. This study assessed the association between self-rated adherence and systolic blood pressure, low-density lipoprotein cholesterol levels, cardiovascular events, and all-cause mortality in SPRINT (Systolic Blood Pressure Intervention Trial). Methods and Results A total of 9361 patients randomized to 2 systolic blood pressure target groups, <120 mm Hg (intensive) and <140 mm Hg (standard), self-rated their medication adherence at each visit by marking a scale, ranging from 0% to 100%. Lower and high adherence were defined as scores ≤80% and >80%, respectively. Linear mixed effect regression models and Cox proportional hazard models were used to evaluate the association between self-rated adherence and systolic blood pressure and low-density lipoprotein cholesterol and cardiovascular events and all-cause mortality, respectively. A total of 9278 participants (mean age 68±9.4 years, 35.6% female) had repeated self-rated adherence measurements available, with a mean of 15±4 measurements per participant over 3.8 years follow-up. Of these, 2694 participants (29.0%) had ≥1 adherence measurements ≤80%. Compared with high-adherent patients, patients with lower adherence had significantly higher estimated on-treatment systolic blood pressure at 2-year follow-up: 128.7 (95% CI, 127.6-129.9) versus 120.0 (95% CI, 119.7-120.2) mm Hg in the intensive arm; and 139.8 (95% CI 138.4-141.1) versus 135.0 (95% CI 134.7-135.2) in the standard arm. Moreover, lower adherence was associated with an estimated 11 mg/dL higher low-density lipoprotein cholesterol level, more cardiovascular events (hazard ratio [HR], 1.69 [95% CI, 1.20-2.39]), and higher all-cause mortality (HR, 1.63 [95% CI, 1.16-2.31]). Conclusions Self-rated adherence allows identification of lower medication adherence and correlates with blood pressure control, low-density lipoprotein cholesterol levels, and adverse outcomes.
Keywords: LDL cholesterol; adverse cardiovascular outcomes; blood pressure; medication adherence.