Our aim was to identify risk factors for coronary heart disease (CHD) events among asymptomatic persons with low (≤130 mg/dl) low-density lipoprotein cholesterol (LDL-C).
Even among persons with low LDL-C, some will still experience CHD events and may benefit from more aggressive pharmacologic and lifestyle therapies.
The MESA (Multi-Ethnic Study of Atherosclerosis) is a prospective cohort of 6,814 participants free of clinical cardiovascular disease. Of 5,627 participants who were not receiving any baseline lipid-lowering therapies, 3,714 (66%) had LDL-C ≤130 mg/dl and were included in the present study. Unadjusted and adjusted hazard ratios were calculated to assess the association of traditional risk factors and biomarkers with CHD events. To determine if subclinical atherosclerosis markers provided additional information beyond traditional risk factors, coronary artery calcium (CAC) and carotid intima media thickness were each separately added to the multivariable model.
During a median follow-up of 5.4 years, 120 (3.2%) CHD events were observed. In unadjusted analysis, age, male sex, hypertension, diabetes mellitus, low high-density lipoprotein cholesterol (HDL-C), high triglycerides, and subclinical atherosclerosis markers (CAC >0; carotid intima media thickness ≥1 mm) predicted CHD events. Independent predictors of CHD events included age, male sex, hypertension, diabetes, and low HDL-C. After accounting for all traditional risk factors, the predictive value of CAC was attenuated but remained highly significant. The relationship of all independent clinical predictors remained robust even after accounting for elevated CAC.
Among persons with low LDL-C, older age, male sex, hypertension, diabetes, and low HDL-C are associated with adverse CHD events. Even after accounting for all such variables, the presence of CAC provided incremental prognostic value. These results may serve as a basis for deciding which patients with low LDL-C may be considered for more aggressive therapies.