What are the different risk groups for hyperlipidemia management according to the American Heart Association (AHA), American College of Cardiology (ACC), and American Association of Clinical Endocrinologists (AACE) guidelines?

Risk Groups for Hyperlipidemia Management Across AHA, ACC, and AACE Guidelines

The American Heart Association (AHA), American College of Cardiology (ACC), and American Association of Clinical Endocrinologists (AACE) guidelines differ significantly in their risk stratification approaches for hyperlipidemia management, with the ESC/EAS and AACE guidelines using more granular risk categories than the AHA/ACC guidelines. 1

AHA/ACC Risk Stratification

The AHA/ACC guidelines stratify patients into the following risk groups:

1. Secondary Prevention Cohort:

   • Very High-Risk: Limited to secondary prevention patients with:
     • History of multiple major ASCVD events OR
     • A major ASCVD event and multiple high-risk conditions 1
   • High-Risk: Other patients with established ASCVD

2. Primary Prevention Cohort:

   • High-Risk: ≥20% 10-year ASCVD risk
   • Intermediate-Risk: 7.5% to <20% 10-year ASCVD risk
   • Borderline-Risk: 5% to <7.5% 10-year ASCVD risk
   • Low-Risk: <5% 10-year ASCVD risk 1

3. Special Populations:

   • Diabetes Mellitus: Subdivided by presence/absence of risk-enhancing factors
   • Severe Primary Hypercholesterolemia: LDL-C ≥190 mg/dL 1

The AHA/ACC guidelines use the Pooled Cohort Equations (PCE) for risk assessment, which predicts both fatal and nonfatal ASCVD events 1, 2.

ESC/EAS Risk Stratification (European Guidelines)

The European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) guidelines, which are often referenced alongside American guidelines, use a different approach:

1. Very High-Risk:

   • Documented ASCVD (clinical or unequivocal on imaging)
   • Diabetes with target organ damage OR ≥3 major risk factors OR type 1 DM with duration >20 years
   • CKD with eGFR <30 mL/min per 1.73 m²
   • Calculated SCORE ≥10% for 10-year risk of fatal CVD
   • FH with ASCVD OR with another major risk factor 1

2. High-Risk:

   • SCORE 5% to <10% for 10-year risk of fatal CVD 1

3. Moderate-Risk:

   • SCORE 1% to <5% for 10-year risk of fatal CVD 1

4. Low-Risk:

   • SCORE <1% for 10-year risk of fatal CVD 1

The ESC/EAS guidelines use the SCORE calculator, which only predicts fatal cardiovascular events 1.

AACE Risk Stratification

The AACE guidelines use a more detailed risk categorization system:

1. Extreme Risk:

   • Progressive ASCVD including unstable angina after achieving LDL-C <70 mg/dL
   • Established clinical cardiovascular disease in patients with DM, CKD 3/4, or heterozygous FH
   • History of premature ASCVD (<55 years male, <65 years female) 3, 4

2. Very High Risk:

   • Established or recent hospitalization for ACS, coronary, carotid or peripheral vascular disease
   • Diabetes or CKD 3/4 with one or more risk factors
   • Heterozygous FH 3, 4

3. High Risk:

   • ≥2 risk factors and 10-year risk >10%
   • Diabetes or CKD 3/4 with no other risk factors 3, 4

4. Moderate Risk:

   • ≤2 risk factors and 10-year risk <10% 3, 4

5. Low Risk:

   • No risk factors 3, 4

Key Differences in Risk Assessment Approaches

1. Risk Calculator:

   • AHA/ACC: Uses PCE (predicts fatal and nonfatal events)
   • ESC/EAS: Uses SCORE (predicts only fatal events)
   • AACE: Uses multiple factors including traditional risk calculators 1, 2

2. Definition of Very High-Risk:

   • AHA/ACC: Limited to secondary prevention with multiple events or high-risk conditions
   • ESC/EAS: Broader definition including selected primary prevention patients
   • AACE: Includes both established ASCVD and specific high-risk primary prevention scenarios 1, 3

3. Subclinical ASCVD:

   • AHA/ACC: CAC score used as a risk modifier but doesn't define risk categories
   • ESC/EAS: Includes unequivocal subclinical ASCVD on imaging in very high-risk category
   • AACE: Considers subclinical atherosclerosis as a risk factor 1

4. Treatment Targets:

   • AHA/ACC: Focuses on percentage LDL-C reduction rather than specific targets
   • ESC/EAS: Provides specific LDL-C targets based on risk category
   • AACE: Provides specific LDL-C targets that are more aggressive than other guidelines 1, 3

Clinical Implications

The differences in risk stratification across these guidelines have important implications for clinical practice:

• The AACE guidelines generally recommend more aggressive LDL-C targets compared to AHA/ACC
• ESC/EAS and AACE guidelines include subclinical atherosclerosis in risk assessment more prominently
• AHA/ACC guidelines place greater emphasis on shared decision-making, especially for borderline and intermediate-risk patients 1

When implementing these guidelines, clinicians should be aware that the same patient might be classified into different risk categories depending on which guideline is followed, potentially leading to different treatment recommendations.