What are the indications for checking Apolipoprotein B (Apo B) and high-sensitivity C-reactive protein (hs-CRP)?

From the Guidelines

Apolipoprotein B (Apo B) and high-sensitivity C-reactive protein (hs-CRP) tests should be used to assess cardiovascular risk in specific patient populations, with Apo B indicated for patients with established cardiovascular disease, family history of premature heart disease, diabetes, metabolic syndrome, or discordant lipid profiles, and hs-CRP testing indicated for intermediate-risk patients (10-20% 10-year cardiovascular risk) and those with family history of premature cardiovascular disease. The most recent and highest quality study, 1, provides guidance on the use of Apo B and hs-CRP in cardiovascular risk assessment. Key points to consider when using these tests include:

• Apo B provides a direct count of atherogenic particles and may better predict cardiovascular risk than LDL alone
• Hs-CRP testing is useful for assessing inflammation and cardiovascular risk, particularly in intermediate-risk patients
• Both tests can help refine treatment decisions, particularly regarding statin intensity or when considering additional lipid-lowering therapies
• Neither test requires special preparation, though hs-CRP should be measured when patients are free of acute illness or inflammation to avoid falsely elevated results
• Elevated hs-CRP levels above 2 mg/L suggest increased cardiovascular risk, and Apo B levels above 130 mg/dL may indicate high cardiovascular risk
• The use of Apo B and hs-CRP should be considered in the context of overall cardiovascular risk assessment, including traditional risk factors and other biomarkers. As stated in 1, the measurement of Apo B and hs-CRP can be useful in assessing cardiovascular risk and guiding treatment decisions, particularly in patients with intermediate or high cardiovascular risk. It is also important to consider the potential limitations and uncertainties of these tests, as well as the need for further research to fully understand their role in cardiovascular risk assessment and management, as noted in 1 and 1. Overall, the use of Apo B and hs-CRP can be a valuable tool in the assessment and management of cardiovascular risk, but should be considered in the context of overall clinical judgment and patient-specific factors.

From the Research

Indications to Check Apo B and High Sensitivity CRP

• Apolipoprotein B (apoB) is considered a more accurate measure of cardiovascular risk and a better guide to the adequacy of lipid lowering than low-density lipoprotein cholesterol (LDL-C) or non-high-density lipoprotein cholesterol (non-HDL-C) 2, 3
• The 2019 European Society of Cardiology/European Atherosclerosis Society Guidelines recommend apoB as a primary metric to guide statin/ezetimibe/PCSK9 therapy 2
• High-sensitivity C-reactive protein (hsCRP) is considered a major predictor of cardiovascular events, and its level is associated with apoB and other cardiovascular risk factors 4
• The relationship between hsCRP and apoB suggests that apoB may play a role in vascular inflammation, but abdominal obesity is a stronger determinant of chronic inflammatory status 4

Clinical Markers of Cardiovascular Risk

• ApoB is a direct measure of circulating numbers of atherogenic lipoproteins and is considered a more reliable indicator of risk than LDL-C 3, 5
• Non-HDL cholesterol includes the assessment of remnant lipoprotein cholesterol, an additional risk factor independent of LDL cholesterol, but apoB is a more accurate marker of cardiovascular risk 5
• Discordance analysis of non-HDL cholesterol versus apoB demonstrates that apoB is the more accurate marker of cardiovascular risk 5

Treatment Targets for Atherosclerotic Cardiovascular Disease

• Guidelines propose using non-HDL cholesterol or apoB as a secondary treatment target to reduce residual cardiovascular risk of LDL-targeted therapies 5
• ApoB is superior to non-HDL cholesterol as a secondary target in patients with mild-to-moderate hypertriglyceridemia, diabetes, obesity or metabolic syndrome, or very low LDL cholesterol [< 70 mg/dL] 5
• Ezetimibe/simvastatin (E/S) provides a therapeutic option to type 2 diabetes patients for lowering not only LDL-C, but also non-HDL-C, apoB, and hsCRP 6