Abstract 4166: Clinical Significance of HDL-c Levels among Patients with LDL-c less than 60 mg/dl
Background: Although studies support an inverse correlation between HDL-cholesterol levels and cardiovascular risk, the clinical relevance of HDL in the context of low LDL levels remains uncertain.
Methods: We identified 6,357 consecutive patients seen at the Palo Alto VA Medical Center or one of 7 community clinics with LDL levels less than 60 mg/dl. The cohort was divided into quartiles based on HDL. The combined primary outcome was myocardial infarction (defined as a Tn I > 0.1 ng/ml) or hospitalization for ischemic heart disease (IHD) at one year. Odds ratios were adjusted for demographics, medical history, laboratory values (hemoglobin, creatinine, HbA1C, liver function tests, LDL, triglycerides), and statin use.
Results: The cohort had a mean age of 65 years, a prior diagnosis of IHD in 42%, diabetes in 46%, hypertension in 73%, and heart failure in 15%. Mean HDL levels (mg/dl) by quartile were: Q1 - 28, Q2 - 36, Q3 - 43, Q4 - 64. The incidence of the combined endpoint of MI or IHD hospitalization at one year was higher in the low HDL quartiles (Q1 - 8.5%, Q2 - 5.8%, Q3 - 5.1%, Q4 - 3.9%, p < 0.0001). The association of HDL with IHD admission and MI persisted following multivariate adjustment (Figure⇓).
Conclusions: Low HDL-cholesterol levels are a marker for excess coronary risk among patients with an LDL less than 60 mg/dl. HDL-directed therapies may play an important role in the prevention of IHD events across all levels of LDL.