Adherence to Cardiovascular Therapy: A Meta-Analysis of Prevalence and Clinical Consequences
Does adherence to heart medications influence risk for cardiovascular disease (CVD) and all-cause mortality?
A systematic review and meta-analysis of prospective epidemiological studies (cohort, nested case–control, or clinical trial) identified through electronic searches using MEDLINE, Web of Science, EMBASE, and Cochrane databases, published between January 1960 and August 2012, was used to identify populations to include in this analysis. Studies were included with the following criteria: an adult population (≥18 years old) and reporting risk estimates of CV medication adherence with any CVD (defined as any fatal or nonfatal coronary heart disease, stroke, or sudden cardiac death) and/or all-cause mortality (defined as mortality from any cause) outcomes.
Data were available on 1,978,919 unique participants with 135,627 CVD and 94,126 all-cause mortality events collected over an average follow-up between 1 and 10 years. The average age of the participants was 63.1 years, and 55% of the participants were male. Seventeen studies were based in Europe, 21 in North America, three in Asia-Pacific, and three were conducted in multiple countries. Overall, 60% (95% confidence interval [CI], 52-68%) of included participants had good adherence (adherence ≥80%) to CV medications. The relative risks (RRs) (95% confidence interval) of development of CVD in those with good versus poor (<80%) adherence were 0.85 (0.81-0.89) and 0.81 (0.76-0.86) for statins and antihypertensive medications, respectively. Corresponding RRs of all-cause mortality were 0.55 (0.46-0.67) and 0.71 (0.64-0.78) for good adherence to statins and antihypertensive agents. These associations remained consistent across subgroups representing different study characteristics. Estimated absolute risk differences for any CVD associated with poor medication adherence were 13 cases for any vascular medication, nine cases for statins, and 13 cases for antihypertensive agents, per 100,000 individuals per year.
The investigators concluded that a substantial proportion of people do not adhere adequately to CV medications, and the prevalence of suboptimal adherence is similar across all individual CVD medications. A significant proportion of all CVD events (~9% in Europe) could be attributed to poor adherence to vascular medications alone. The level of optimal adherence confers a significant inverse association with subsequent adverse outcomes.
This meta-analysis highlights the importance of medication adherence. Efforts to identify barriers to medication adherence would likely translate into reduction in CVD events.
Keywords: Risk, Coronary Artery Disease, North America, Stroke, Follow-Up Studies, Hydroxymethylglutaryl-CoA Reductase Inhibitors, Coronary Disease, Europe, Medication Adherence, Prevalence, Antiretroviral Therapy, Highly Active, Death, Cardiovascular Diseases, Confidence Intervals
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