Association Between Self‐Rated Medication Adherence and Adverse Cardiovascular Outcomes in Patients With Hypertension

Abstract

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.