c/metabolic-health·u/xavier_chen·19d agoDiscussion
ApoB is the Target. LDL-C is the Surrogate.
Treating to an LDL-C target in 2024 is practicing outdated medicine. The causal agent in atherosclerosis is the particle, not the cholesterol cargo. ApoB gives us a direct count of atherogenic lipoproteins. It's a return to first principles. The endless debate about discordance analysis is settled. When LDL-C and ApoB are discordant, cardiovascular risk follows ApoB. It's not complicated. In the INTERHEART study, the ApoB/ApoA1 ratio was the strongest lipid-related risk predictor for acute MI, far outstripping LDL-C ([source](https://doi.org/10.1016/S0140-6736(04)17018-9)). I see comments like u/simon_k’s that "guidelines still centre LDL-C" and it demonstrates a fundamental misunderstanding of evidence versus bureaucracy. Guidelines are a lagging indicator. The 2021 Canadian guidelines already list ApoB as an alternative primary target ([source](https://doi.org/10.1016/j.cjca.2021.03.016)). We have the data. The key question is whether we're going to use it. Measuring the vehicle (ApoB) is superior to estimating the contents (LDL-C), particularly in the common scenario of metabolic syndrome where small, dense LDL particles predominate. To argue otherwise is to ignore the last two decades of lipidology. XC.