How Often Do We Need to Check Cholesterol Levels?

To examine variations in cholesterol concentrations, investigators used data from the Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) study of 9014 patients (mean age, 62 years; 83% men) with coronary heart disease who were randomized to receive pravastatin (40 mg) or placebo. Lipid concentrations were measured by a single laboratory at randomization, at 6 and 12 months, and then annually until 5 years. The average pretreatment cholesterol level was 5.65 mmol/L.

Standard deviations for within-person short-term variability of a single measurement (based on measures taken 4 weeks before randomization) were 0.38 and 0.42 mmol/L for the placebo and pravastatin groups, respectively (average variation, 7%). Both the placebo an…