Abstract
INTRODUCTION: A high proportion of Canadian patients with acute myocardial infarction (AMI) do not achieve the threshold low-density lipoprotein cholesterol (LDL-C) levels recommended by the Canadian Cardiovascular Society in 2021. This increases the risk of subsequent atherosclerotic cardiovascular disease (ASCVD) events. Here, we assess LDL-C levels and threshold achievement among patients by lipid-lowering therapies (LLT) received post-AMI. METHODS: A retrospective cohort study of patients identified with AMI between 2015 and 2019 was conducted using administrative health databases in Alberta, Canada. Patients were grouped by their highest-intensity LLT post-AMI (proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) + another LLT; PCSK9i alone; ezetimibe + statin; statins (high, moderate, low intensity); or ezetimibe alone), and available LDL-C levels were examined in the year before and after LLT dispense date. RESULTS: The cohort included 15,283 patients. In patients on PCSK9i + LLT, the median [95% confidence interval (CI)] LDL-C levels decreased from 2.7 (2.3-3.4) before to 0.9 (0.5-1.2) mmol/l after treatment, the largest decrease among treatment groups. In the ezetimibe + statin and high-intensity statin groups, median (95% CI) values after treatment were 1.5 (1.5-1.6) and 1.4 (1.4-1.4) mmol/l, respectively. The proportion of patients below the 1.8 mmol/l threshold increased by 77.7% in the PSCK9i + LLT group after treatment, compared to 45.4 and 32.4% in the ezetimibe + statin and high-intensity statin groups, respectively. CONCLUSIONS: Intensification with PCSK9i in AMI patients results in a greater proportion of patients achieving below the recommended LDL-C threshold versus statins and or ezetimibe alone. Increased focus on achieving below the LDL-C thresholds with additional LLT as required may benefit patient cardiovascular outcomes.