Plasma concentration of apolipoprotein B is a slightly better predictor of coronary heart disease than is non-HDL cholesterol and a much better predictor than is LDL cholesterol, reported Dr. Tobias Pischon of the Harvard School of Public Health, Boston, and his associates.
This finding is sure to add to the controversy over which lipid measurement is the best for assessing both coronary risk and treatment efficacy. Current National Cholesterol Education Program guidelines recommend LDL cholesterol as the primary target for lipid-lowering therapy. The guidelines consider HDL cholesterol a secondary treatment target and do not consider apolipoprotein B (apo B) a target at all, the investigators said.
Apo B concentration is a measure of the particle concentration of all atherogenic lipoproteins, whereas LDL and non-HDL cholesterol levels are measures of some of the cholesterol carried by these particles. Dr. Pischon and his associates conducted what they said was the first large prospective study to directly compare these three measures as predictors of coronary heart disease (CHD) risk.
Their results indicated that apo B is the best such predictor, and also that particle concentration of atherogenic lipoproteins is more crucial than is cholesterol content in the development of CHD (Circulation 2005;112:3375–83).
The researchers used a database of more than 51,000 male health professionals who had been followed every 2 years since 1986 to identify 243 subjects who had developed CHD during a 6-year study period and 496 matched control subjects who did not develop CHD. The baseline apo B level was the best predictor of CHD (relative risk 2.98). Non-HDL cholesterol also was strongly predictive (RR 2.75), with LDL cholesterol less so (RR 2.07).
In an editorial comment accompanying the report, Dr. Allan D. Sniderman of McGill University, Montreal, said that apo B should replace LDL and non-HDL cholesterol as the measurement of choice in assessing CHD risk, noting that it has now been more extensively validated in both epidemiologic studies and clinical trials. Measurement of apo B is already standardized, automated, and inexpensive, he said (Circulation 2005;112:3366–7).
In contrast, Dr. Margo A. Denke of the University of Texas Health Science Center at San Antonio said that abandoning cholesterol testing in favor of apo B testing would be too confusing for both physicians and the public. The cholesterol content of lipoprotein particles reliably predicted CHD in every major study, whereas apo B assessments have not consistently improved that prediction, she said (Circulation 2005;112:3368–70).