Introduction

In this issue, Seo et al, on behalf of all participants in the COACT (Catholic University of Korea–percutaneous coronary intervention) registry, report that after placement of a drug-eluting stent in patients with coronary artery disease (CAD) and well controlled low-density lipoprotein (LDL-C) serum levels below 100 mg/dl, the high-density lipoprotein (HDL-C) serum concentrations remain a significant prognostic indicator of future cardiovascular events.1 The authors dichotomised the patient cohort according to HDL-C levels (40 mg/dl for men or 50 mg/dl for women) and compared major adverse cardiovascular event rates (MACE). Patients with low HDL-C levels (<40 mg/dl for men or <50 mg/dl for women) had a 40% higher rate of major adverse cardiac events (MACE), including all-cause death, non-fatal myocardial infarction and target vessel revascularisation (adjusted HR 1.404, 95% CI 1.111 to 1.774, p=0.004).

Their well conducted study confirms the results of a post-hoc analysis of the Treating to New Targets trial, in which a 39% lower risk for cardiovascular events was observed for patients with stable CAD in the highest versus lowest HDL-C quintile—even under statin therapy and LDL-C levels <100 mg/dl.2 In contrast to Treating to New Targets, however, Seo et al assessed the risk reduction in a post-interventional CAD cohort recruited for a national registry, thus reflecting a more ‘real-world’ scenario.

However, there are also some caveats in a registry as compared to a prospective randomised trial: patients with low HDL-C were more likely to present with acute coronary syndrome (ACS), had a 10.3% higher prevalence of diabetes mellitus, and a 5.8% higher prevalence of arterial hypertension (see their table 1). To exclude that the higher …