Abstract 38: A Novel Two-Question Antihypertensive Medication Adherence Scale Predicts Blood Pressure Control and Cardiovascular Disease Outcomes

Abstract

Introduction: Poor medication adherence is a major contributor to uncontrolled hypertension, the leading preventable risk factor for CVD and mortality worldwide. Simple and accessible tools are needed to quantify medication adherence. We developed a novel two-question adherence scale in the Implementation of Multifaceted Patient-Centered Treatment Strategies for Intensive Blood Pressure Control (IMPACTS) trial and tested its prediction of BP control and CVD. Methods: We collected data on the IMPACTS Medication Adherence Scale (IMPACTS-MAS) and the eight-item Morisky Medication Adherence Scale (MMAS-8) in 1,206 IMPACTS participants. The IMPACTS-MAS consists of two questions, (1) “Over the last 7 days, on how many days did you not take any BP pills”, and (2) “Over the last 7 days, on how many days did you cut back on your BP pills?” and is categorized as low or high adherence. Linear and logistic mixed effects regressions examined the association between IMPACTS-MAS, MMAS-8, and uncontrolled BP. We also assessed IMPACTS-MAS in 33,995 China Rural Hypertension Control Project (CRHCP) participants studied at baseline and followed for CVD outcomes during a 36 month period. Cox regression examined the association between IMPACTS-MAS and CVD outcomes adjusting for treatment group, age, sex, education, and history of CVD. Results: The IMPACTS participants had an average age of 58 years and 56% (676/1,206) were female. Compared to high adherence, low adherence on IMPACTS-MAS and MMAS-8 was associated with 3.5 (95% CI: 1.9,5.1) and 2.6 (1.1,4.1) mmHg higher SBP , 2.5 (1.3,3.7) and 2.0 (0.87,3.1) higher DBP , and 73% [OR=1.73 (1.27,2.36)] and 68% [OR=1.68 (1.27,2.23)] higher uncontrolled BP (≥140/90 mmHg), respectively. The CRHCP participants had an average age of 63 years and 61% (20,825/33,995) were female. Compared to high adherence, low adherence on IMPACTS-MAS was associated with 3.6 mmHg (3.2,4.0) higher SBP , 0.89 mmHg (0.76,1.0) higher DBP , and with 42% [OR=1.42 (1.37,1.47)] higher uncontrolled BP , during follow-up. Further, low adherence was associated with 53% [HR=1.53 (1.30,1.81)] higher levels of CVD , 88% [HR=1.88 (1.11,3.17)] higher levels of myocardial infarction , and 54% [HR=1.54 (1.28,1.86)] higher levels of stroke during follow-up. Finally, low adherence was associated with 51% [HR=1.51 (1.31,1.75)] higher levels of CVD death and 47% [HR=1.47 (1.31,1.65)] higher levels of all-cause mortality , during follow-up. Conclusion: The novel two-question IMPACTS-MAS score is associated with BP control and predicts CVD outcomes and mortality in diverse populations. It is a simple, accessible tool that can be used in research and clinical practice to identify medication nonadherence.