Clinical characteristics and coronary risk factors of patients with low concentrations of serum low-density lipoprotein cholesterol and total cholesterol.

We investigated the clinical characteristics and coronary risk factors of Chinese patients with suspected coronary artery disease (CAD) having low serum concentrations of both low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC). Of 1,450 patients with suspected CAD (age range, 30-92 years; 948 men and 502 women), 760 had established CAD. The patients were divided into three groups according to lipid profile patterns. Group 1 patients (n = 138) had low LDL-C concentrations (< 100 mg/dL) and low TC concentrations (< 160 mg/dL). They were characterized by lower triglyceride concentrations, lower frequencies of high TC/high-density lipoprotein cholesterol (HDL-C) ratios (> 5) and LDL-C/HDL-C ratios (> 5), and lower frequencies of a family history of CAD and obesity. Group 3 patients (n = 610) had LDL-C concentrations of 130 mg/dL or above and TC concentrations of 200 mg/dL or above, much higher than in group 1. The prevalence of CAD was 41.3% (57/138) in group 1. 46.7% (328/702) in group 2, and 61.5% (375/610) in group 3. Groups with higher TC and LDL-C concentrations had a higher CAD prevalence. Coronary risk factors of group 1 patients appeared to be low HDL-C concentration, high TC/HDL-C ratio, advanced age, cigarette smoking, hypertension, and diabetes mellitus. Among these risk factors, HDL-C and hypertension were independent predictors of CAD. Unlike in the other two groups, hypertension was the only independent nonlipid risk factor. We conclude that in therapy or prevention of CAD, the goals should be to reduce LDL-C concentration to below 100 mg/dL and the TC concentration to below 160 mg/dL. However, other risk factors should also be considered.