Frequency of low serum high-density lipoprotein cholesterol levels in hospitalized patients with “desirable” total cholesterol levels

Abstract

Because the National Cholesterol Education Program guidelines suggest that levels of total serum cholesterol < 5.17 mmol/liter (200 mg/dl) are “desirable,” we performed a retrospective observational analysis to determine the prevalence of coronary artery disease (CAD) in patients with total cholesterol < 5.17 mmol/liter (200 mg/dl) and the prevalence of total cholesterol< 5.17 mmol/liter (200 mg/dl) in patients with CAD by angiography. Cholesterol levels < 5.17 mmol/liter (200 mg/dl) were found in 1,084 of 2,535 patients (42%) having cholesterol measured on hospital admission; 690 of these 1,084 (64%) had CAD. These patients were mostly men, had a family history of premature CAD, and 60% (414 of 690) had high-density lipoprotein (HDL) cholesterol < 0.90 mmol/liter (35 mg/dl). In a separate group of patients defined from the same admission population but having angiographically established CAD, 32% (424 of 1, 197) had a total cholesterol < 5.17 mmol/liter (200 mg/dl), 59% of whom (252 of 424) had HDL < 0.90 mmol/liter (35 mg/dl). An analysis of persons admitted electively for angiography (to exclude any effects of hospitalization per se on serum lipids) revealed a similar proportion of persons with total cholesterol < 5.17 mmol/liter (200 mg/dl) (35%), CAD (82%), and HDL < 0.90 mmol/liter (35 mg/dl). Our observations suggest that low serum cholesterol levels (< 5.17 mmol/liter [200 mg/dl]) are seen frequently in patients suspected of having or who have established CAD; moreover, a false sense of security may be established among physician and patient with the finding of a serum cholesterol level < 5.17 mmol/liter (200 mg/dl) — men with a family history of premature CAD and low levels of HDL characterize persons with CAD in this low cholesterol group.