Are We Moving Towards Concordance on the Principle That Lipid Discordance Matters?

Abstract

In this issue of Circulation , Samia Mora, Julie Buring, and Paul Ridker publish an elegant and clinically-relevant analysis examining discordance of low-density lipoprotein cholesterol (LDL-C) with related laboratory measures and the risk implications.1 The article should attract attention from a diverse set of contingents, such as those based in preventive cardiology, clinical lipidology, and laboratory medicine, to name just a few. The study addresses the underappreciated concept of discordance between different lipid and lipoprotein measures in individual patients. The investigators address the prevalence of such discordance and its association with long-term incidence of coronary events. Article see p 553 Dr Mora and colleagues analyze participants in the prospective Women’s Health Study. With necessary lipid measurements captured on nearly all of the women, the analysis is large, involving 27 533 women aged ≥45 years. This is a primary prevention population—these women were all free of self-reported cardiovascular disease and cancer at baseline. After baseline risk factor measurements, the women underwent follow-up over a median of 17.2 years for incident coronary events, including nonfatal myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting, and coronary death. An Endpoints Committee adjudicated events, which occurred in 1070 women. A unique aspect of this analysis is the simultaneous availability of directly measured LDL-C, Friedewald-estimated LDL-C, nonhigh-density lipoprotein cholesterol (non– HDL-C), apolipoprotein B (apoB), and low-density lipoprotein particle concentration (LDL-P). Essentially, these are related, but distinct, measures of the atherogenic lipid burden. Given that LDL-C is commonly the first parameter considered in clinical practice, in line with international guidelines,2–4 having this study center its primary analyses on LDL-C makes the results particularly relevant to daily practice. Another strength of the study is that the laboratory performing the measurements participates in the Centers for Disease Control and Prevention’s Lipid Standardization Program. Ultimately, …