A Translational Tool to Facilitate Use of Apolipoprotein B for Clinical Decision-Making

Background Despite recent large-scale discordance studies showing definitively that atherosclerotic cardiovascular disease (ASCVD) risk correlates better with apolipoprotein B (apoB) than with low-density lipoprotein cholesterol (LDL-C), the latter remains the recommended metric for guiding lipid-lowering treatment decisions in the United States. A major barrier to change, in this regard, is the lack of guideline-recommended apoB treatment targets. We developed a simple method to translate apoB values into population-equivalent LDL-C units, allowing apoB-based treatment decisions to be made using LDL-C targets. Methods Sequentially collected, population-based samples underwent standard lipid panel analysis and apoB testing by immunoassay. Those with triglycerides greater than 1000 mg/dl were excluded, leaving a study cohort of 15 153 individuals. Results Linear regression of calculated LDL-C values against percentile-equivalent apoB values yielded an equation to convert apoB into percentile-equivalent LDL-C units: [LDL-C equivalents = 1.38(apoB) - 29] (R-2 = 0.999). The extent of discordance between LDL-C and apoB was examined in subgroups with similar LDL-C, ranging from very low (55-70 mg/dL) to very high (175-190 mg/dL). Among individuals with very low LDL-C, 40% had discordantly higher apoB, indicating higher ASCVD risk. Of those with very high LDL-C, 49% had discordantly lower apoB. Across the range, a minority of patients (25%-40%) had concordant levels of apoB, confirming that discordance between these biomarkers is highly prevalent. Similar results were found in discordance analysis between apoB and non-high-density lipoprotein cholesterol (HDL-C). Conclusions Providing visibility to discrepancies among LDL-C, non-HDL-C, and apoB should help to facilitate more rapid and widespread adoption of apoB for managing ASCVD risk.

Automated summary

Despite recent studies showing better correlation between atherosclerotic cardiovascular disease (ASCVD) risk and apolipoprotein B (apoB) than with low-density lipoprotein cholesterol (LDL-C), treatment decisions in the United States still rely on LDL-C. This study developed a method to convert apoB values into LDL-C units, allowing the use of LDL-C targets for apoB-based treatment decisions.