What is the target level for Apolipoprotein B (Apo B)?

Target Levels for Apolipoprotein B (Apo B)

For patients with very high cardiovascular risk, the Apo B target should be <80 mg/dL, while for those with high cardiovascular risk, the target should be <100 mg/dL. 1

Risk Stratification and Corresponding Apo B Targets

Very High Risk Patients (Apo B target <80 mg/dL):

• Patients with established cardiovascular disease (CVD)
• Patients with type 2 diabetes and target organ damage or additional risk factors
• Patients with chronic kidney disease (CKD)
• Patients with familial hypercholesterolemia (FH)

High Risk Patients (Apo B target <100 mg/dL):

• Patients with type 2 diabetes without additional risk factors
• Patients with multiple risk factors for CVD

Clinical Significance of Apo B

Apo B is the main apoprotein of atherogenic lipoproteins and provides a direct measure of the number of atherogenic particles in circulation 1. Each atherogenic lipoprotein particle (including LDL, VLDL, IDL, and remnant particles) contains exactly one molecule of Apo B, making it a precise indicator of total atherogenic burden.

Key advantages of Apo B measurement:

• Better index of adequacy of LDL-lowering therapy than LDL-C 1
• Less laboratory error in determination compared to LDL-C, particularly in patients with hypertriglyceridemia 1
• More accurate risk assessment in patients with:
  • Diabetes mellitus
  • Metabolic syndrome
  • Hypertriglyceridemia

Relationship to Other Lipid Parameters

Apo B can be used as a substitute for LDL-C in risk assessment 1. When both LDL-C and Apo B are measured:

• If LDL-C is at target but Apo B remains elevated, there may be residual risk from small dense LDL particles or remnant lipoproteins
• When triglycerides are <1.5 mmol/L, Apo B and LDL-C correlate very well 2
• When triglycerides are ≥1.5 mmol/L, discordance between Apo B and LDL-C increases 2

Treatment Considerations

The primary approach to achieving Apo B targets involves:

1. Intensive statin therapy as first-line treatment 1
2. Addition of ezetimibe if targets are not achieved with statins alone 1
3. PCSK9 inhibitors may be considered for very high-risk patients not achieving targets with maximum tolerated statin plus ezetimibe

Common Pitfalls and Caveats

• Relying solely on LDL-C may underestimate cardiovascular risk, especially in patients with normal LDL-C but increased numbers of small, dense LDL particles 3
• Approximately one-third of patients with type 2 diabetes meet both LDL-C and Apo B goals simultaneously, highlighting the importance of measuring both parameters 2
• Among patients who fail to achieve LDL-C targets, 28-39% may still meet Apo B targets, indicating potential misclassification of risk when using LDL-C alone 2
• Recent evidence suggests Apo B is superior to LDL-C and non-HDL-C for guiding lipid-lowering therapy and assessing cardiovascular risk 4

While Apo B is not universally measured in all clinical laboratories, its clinical utility is increasingly recognized, particularly for patients with metabolic disorders where standard lipid measurements may not accurately reflect cardiovascular risk.