Initiation and maintenance of statins and aspirin after acute coronary syndromes (ANZACS-QI 11)

Abstract

ABSTRACT INTRODUCTION Prior New Zealand studies suggest that only approximately two-thirds of patients who present with an acute coronary syndrome (ACS) are maintained on a statin/aspirin post-discharge. This could be due to sub-optimal initiation or poor longer-term adherence. AIM To identify the pattern of statin/aspirin maintenance following ACS from initial prescription to 3 years post-discharge. METHODS All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry data for consecutive New Zealand residents (2007–2011), who were hospitalised with ACS, were anonymously linked to national datasets to derive a medication possession ratio (MPR) to assess medication maintenance. An MPR ≥ 0.8 is considered adequate maintenance. RESULTS Of the 1846 patients discharged alive, 95% were prescribed a statin at discharge and 92% were dispensed a statin within 3 months, but only 75% had a MPR ≥ 0.8 in the first year, and 67% in year 3. In the same cohort, 98% were prescribed aspirin and 88% were dispensed aspirin within the 3 months of discharge. In the first year, 72% had an aspirin MPR ≥ 0.8 and 71% maintained this in year 3. Fifty-nine percent were maintained on both aspirin and a statin in the third year, but 20% were maintained on neither. Regression analysis identified the independent predictors of inadequate maintenance in the third year as age < 45 years, no prior statin, and Māori and Pacific ethnicity. CONCLUSION Longer-term maintenance of evidenced-based secondary prevention medications after ACS is suboptimal despite high levels of initial prescribing and dispensing. Understanding the barriers to longer-term maintenance is required to improve patient outcomes.