High density lipoprotein cholesterol in coronary artery disease: when higher means later

Area of Science:

• Cardiology
• Lipid Metabolism
• Clinical Research

Background:

• High-density lipoprotein cholesterol (HDL-C) is typically associated with reduced cardiovascular risk.
• However, elevated HDL-C levels do not always confer protection, as some patients with high HDL-C develop coronary artery disease (CAD) and cardiac events.

Purpose of the Study:

• To characterize the clinical profile of CAD patients with elevated HDL-C.
• To evaluate the prognostic significance of elevated HDL-C in patients with established CAD.

Main Methods:

• Prospective study of 2322 patients with chronic CAD (defined by coronary stenosis or myocardial infarction).
• Patients were categorized by HDL-C levels: low (<35 mg/dL), normal (35-60 mg/dL), and high (>60 mg/dL).
• Clinical characteristics and cardiac event-free survival were assessed during a median follow-up of 46 months.

Main Results:

• Elevated HDL-C was observed in 5% of patients (n=122).
• Patients with elevated HDL-C were less likely to be male, smokers, or diabetic, but were older.
• Cardiac event-free survival was lower in low HDL-C group compared to normal HDL-C group, but not significantly different in the elevated HDL-C group.
• The adverse prognostic impact of low HDL-C was independent of multiple clinical factors.
• The prognostic impact of elevated HDL-C was not significant after adjustment for age.

Conclusions:

• Patients with elevated HDL-C experience CAD and cardiac events, similar to those with low or normal HDL-C.
• These events tend to occur at an older age in individuals with high HDL-C.
• Elevated HDL-C may not be a protective factor in the context of established CAD, especially when considering age as a confounding factor.