Association Between Medication Adherence and 1-Year Major Cardiovascular Adverse Events After Acute Myocardial Infarction in China

Abstract

Background Secondary prevention after acute myocardial infarction ( AMI ) requires long-term guideline-directed medical therapy. However, the level of medication adherence, factors associated with poor adherence, and extent to which good adherence can reduce adverse events after AMI in China remain uncertain. Methods and Results In 2013 to 2014, 4001 AMI patients aged ≥18 years were discharged alive from 53 hospitals across China (mean age 60.5±11.7 years; 22.7% female). Good adherence was defined as taking medications (aspirin, β-blockers, statins, clopidogrel, or angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers) ≥90% of the time as prescribed. Cox models assessed the association between good adherence (a time-varying covariate) and 1-year cardiovascular events after AMI . The most common medications were aspirin (82.2%) and statins (80.5%). There were 243 patients who were not prescribed any medications during follow-up; 1-year event rates were higher for these patients (25.1%, 95% CI 19.7-30.6%) versus those taking ≥1 medications (6.6%, 95% CI 5.76-7.34%). The overall rate of good adherence was 52.9%. Good adherence was associated with lower risk of 1-year events (adjusted hazard ratio 0.61, 95% CI 0.49-0.77). The most common reason for poor adherence was belief that one's condition had improved/no longer required medication. More comorbidities and lower education level were associated with poor adherence. Conclusions Good adherence reduced 1-year cardiovascular event risk after AMI . About half of our cohort did not have good adherence. National efforts to improve AMI outcomes in China should focus on medication adherence and educating patients on the importance of cardiovascular medications for reducing risk of recurrent events. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT01624909.

Keywords: acute myocardial infarction; cardiovascular adverse events; medication adherence; patient‐reported outcomes.

Figures

Figure 1

Distribution of prescribed medications over the study period. ACEI indicates angiotensin‐converting enzyme inhibitor; ARB, angiotensin‐receptor blocker.

Figure 2

Number of prescribed medications per patient over the study period.

Figure 3

Kaplan–Meier estimator to show the observed probability of being free from 1‐year major cardiovascular adverse events in the good adherence (score ≥0.90), poor adherence (score

Figure 4

Reasons for not taking medications as prescribed by interview period (top panel: 1 month after discharge, middle panel: 6 months after discharge, and bottom panel: 12 months after discharge). The most frequently reported reason for patients not taking medications as prescribed was, “I think that my condition has improved and do not need to take it.” The proportion of patients reporting this reason increased over time. Take β‐blocker for example; the percentage of patients reporting this reason was 27.4% at 1 month, 42.1% at 6 months, and 45.8% at 12 months. ACEI indicates angiotensin‐converting enzyme inhibitor; ARB, angiotensin‐receptor blocker.