What’s the Utility of the Apo B:Apo A-1 Ratio?

Multiple tests have been touted to improve the prediction of coronary heart disease. Several published clinical guidelines have recommended the use of apolipoprotein B (apo B) for this purpose; however, this approach has not been validated. Therefore, investigators used a variety of techniques to evaluate the relative utility of apo B, apolipoprotein A-1 (apo A-1), serum total cholesterol, HDL cholesterol, LDL cholesterol, non-HDL cholesterol, and three lipid ratios in determining risk for CHD, as well as the relative ability of these measures to reclassify CHD risk. More than 3300 middle-aged, white participants in the Framingham Offspring Study without cardiovascular disease were followed for a median of 15 years.

A total of 291 first CHD events occurred, 198 of them in men. In men, elevations in non-HDL cholesterol, apo B, total cholesterol:HDL ratio, LDL:HDL ratio, and apo B:apo A-1 ratio were all significantly associated with increased CHD risk to a similar degree. Elevated apo A-1 and HDL were likewise associated with reduced CHD risk. Women had results similar to those in men except that decreased apo A-1 was not significantly associated with incident CHD. In sex-specific analyses, elevated LDL and total cholesterol were not significantly associated with increased CHD risk in either men or women, perhaps owing to the lack of statistical power of these substudies. In men, total cholesterol:HDL and apo B:apo A-1 ratios both improved reclassification of 10-year risk for CHD; however, the difference between the two was not significant. In women, neither lipid ratio improved CHD risk reclassification.