Discordance analysis for apolipoprotein and lipid measures for predicting myocardial infarction in statin-treated patients with coronary artery disease: a cohort study

BACKGROUND The optimal apolipoprotein or lipid measures for identifying statin-treated patients with coronary artery disease (CAD) at residual cardiovascular risk remain controversial. This study aimed to compare the predictive powers of apolipoprotein B (apoB), non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL-C), apoB/apolipoprotein A-1 (apoA-1) and non-HDL-C/HDL-C for myocardial infarction (MI) in CAD patients treated with statins in the setting of secondary prevention. METHODS The study included 9191 statin-treated CAD patients with a five-year median follow-up. All measures were analyzed as continuous variables and concordance/discordance groups by medians. The hazard ratio (HR) with 95% CI was estimated by Cox proportional hazards regression. Patients were classified by the clinical presentation of CAD for further analysis. RESULTS The high-apoB-low-LDL-C and the high-non-HDL-C-low-LDL-C categories yielded HR of 1.40 (95% CI: 1.04-1.88) and 1.51 (95% CI: 1.07-2.13) for MI, respectively, whereas discordant high LDL-C with low apoB or non-HDL-C was not associated with the risk of MI. No association of MI with discordant apoB versus non-HDL-C, apoB/apoA-1 versus apoB, non-HDL-C/ HDL-C versus non-HDL-C, or apoB/apoA-1 versus non-HDL-C/HDL-C was observed. Similar patterns were found in patients with acute coronary syndrome. In contrast, no association was observed between any concordance/discordance category and the risk of MI in patients with chronic coronary syndrome. CONCLUSIONS ApoB and non-HDL-C better predict MI in statin-treated CAD patients than LDL-C, especially in patients with acute coronary syndrome. ApoB/apoA-1 and non-HDL-C/HDL-C show no superiority to apoB and non-HDL-C for predicting MI.