ApoB versus non-HDL-cholesterol: diagnosis and cardiovascular risk management.

The most recent guidelines released by the EAS/ESC and the Canadian Cardiovascular Society (CCS) retain low-density lipoprotein cholesterol (LDL-C) as the primary measure of the atherogenic risk of the apolipoprotein B (apoB) lipoproteins and the primary target of LDL-C lowering therapy. Both organizations endorse non-high-density lipoprotein cholesterol (non-HDL-C) and apoB as "alternate/secondary" targets, but neither group offers evidence supporting the continued preference of LDL-C as the primary target over non-HDL-C and apoB. Further, both suggest that non-HDL-C and apoB more or less measure the same thing and, therefore, are essentially interchangeable. But what is the evidence that LDL-C should remain the primary target, and are apoB and non-HDL-C mirror images of one another? Furthermore, are estimation of risk and establishment of treatment targets the only relevant issues, or is diagnosis also an essential objective? These are the questions this article will address. Our principal objectives are: (1) to clarify the differences between LDL-C, non-HDL-C, and apoB and to distinguish what they measure; (2) to summarize the evidence relating to LDL-C, non-HDL-C, and apoB as predictors of cardiovascular risk and as targets for treatment; and (3) to demonstrate that diagnosis of atherogenic dyslipoproteinemias should be a fundamental clinical priority.