Medication nonadherence is associated with a broad range of adverse outcomes in patients with coronary artery disease.
BACKGROUND
Little is known about the effect of nonadherence among patients with coronary artery disease (CAD) on a broad spectrum of outcomes including cardiovascular mortality, cardiovascular hospitalizations, and revascularization procedures.


METHODS
This was a retrospective cohort study of 15,767 patients with CAD. Medication adherence was calculated as proportion of days covered for filled prescriptions of beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, and statin medications. Multivariable Cox regression assessed the association between medication nonadherence as a time-varying covariate and a broad range of outcomes, adjusting for demographics and clinical characteristics. Median follow-up was 4.1 years.


RESULTS
Rates of medication nonadherence were 28.8% for beta-blockers, 21.6% for ACE inhibitors, and 26.0% for statins. In unadjusted analysis, nonadherence to each class of medication was associated with higher all-cause and cardiovascular mortality. In multivariable analysis, nonadherence remained significantly associated with increased all-cause mortality risk for beta-blockers (hazard ratio [HR] 1.50, 95% CI 1.33-1.71), ACE inhibitors (HR 1.74, 95% CI 1.52-1.98), and statins (HR 1.85, 95% CI 1.63-2.09). In addition, nonadherence remained significantly associated with higher risk of cardiovascular mortality for beta-blockers (HR 1.53, 95% CI 1.16-2.01), ACE inhibitors (HR 1.66, 95% CI 1.26-2.20), and statins (HR 1.62, 95% CI 1.124-2.13). The findings of increased risk associated with nonadherence were consistent for cardiovascular hospitalization and revascularization procedures.


CONCLUSIONS
Nonadherence to cardioprotective medications is common in clinical practice and associated with a broad range of adverse outcomes. These findings suggest that medication nonadherence should be a target for quality improvement interventions to maximize the outcomes of patients with CAD.
Ho
P Michael
PM
Cardiology Section, Denver VA Medical Center, Denver, CO, USA. michael.ho@uchsc.edu
Magid
David J
DJ
Shetterly
Susan M
SM
Olson
Kari L
KL
Maddox
Thomas M
TM
Peterson
Pamela N
PN
Masoudi
Frederick A
FA
Rumsfeld
John S
JS
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D010349:Patient Compliance / Q000706:statistics & numerical data; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016019:Survival Analysis; D016312:Treatment Refusal / Q000706:statistics & numerical data*
D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors