Demographic differences in the initiation and maintenance of statins in the first year post ACS in New Zealand: a data linkage study (ANZACS-QI 57).

INTRODUCTION:Prior New Zealand studies suggest that only approximately two-thirds of patients who present with an acute coronary syndrome (ACS) are adequately maintained on a statin post-discharge. This could be due to low initiation and/or poor longer-term adherence. AIM:To identify the pattern and adequacy of statin maintenance following ACS from initial prescription to one-year post-discharge. METHODS:All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry data for consecutive New Zealand residents (2015-2017) who were hospitalised with ACS and managed with coronary angiography 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 and ≥1 is considered optimal. RESULTS:Of the 16,557 patients who survived their ACS, 15,431 (93.2%) were prescribed a statin at discharge and 89.8% were dispensed a statin within three months. 79.8% (13,219/16,557) of patients had an MPR ≥0.8 during the first year, but only 61.0% (10,096/16,557) had optimal dispensing over this period. Regression analysis identified the independent predictors of sub-optimal maintenance over the first year as age <45 years, no prior statin and Māori and Pacific ethnicity. CONCLUSION:After ACS discharge, the gap between prescribing and dispensing rates was small with only minor demographic variation. One in ten patients were not initially dispensed a statin. Although eight in ten patients were adequately maintained, only six in ten had optimal maintenance with clear ethnic and age differences, which may reflect more general disparities in healthcare.