What are the treatment guidelines in Canada for individuals with an elevated Framingham Risk Score (FRS) risk profile?

Canadian Treatment Guidelines for Elevated Framingham Risk Score

In Canada, individuals with FRS ≥20% are classified as high-risk and should receive statin therapy with an LDL-C target of <2.0 mmol/L (approximately 77 mg/dL), while those with FRS 10-19.9% are intermediate-risk and require individualized decision-making based on additional risk factors and potentially coronary artery calcium (CAC) scoring. 1, 2

Risk Stratification Framework

The Canadian Cardiovascular Society uses the Framingham Risk Score to stratify patients into three categories for primary prevention 1:

Low-Risk (FRS <10%)

• Statin therapy is not recommended for most individuals 1
• Exceptions requiring treatment: 1
  • LDL-C ≥5.0 mmol/L (or apoB ≥1.45 g/L or non-HDL-C ≥5.8 mmol/L)
  • FRS 5-9.9% with LDL-C ≥3.5 mmol/L (or non-HDL-C ≥4.2 mmol/L or apoB ≥1.05 g/L), particularly with additional CV risk modifiers such as family history, Lp(a) ≥50 mg/dL, or CAC >0
• Primary focus should be on health behavior modifications 1

Intermediate-Risk (FRS 10-19.9%)

This category requires meeting specific lipid thresholds OR age-based criteria with additional risk factors 1:

Lipid criteria: 1

• LDL-C ≥3.5 mmol/L, OR
• Non-HDL-C ≥4.2 mmol/L, OR
• ApoB ≥1.05 g/L

OR age-based criteria with one additional risk factor: 1

• Men ≥50 years or women ≥60 years PLUS one of:
  • Low HDL-C
  • Impaired fasting glucose
  • High waist circumference
  • Current smoking
  • Hypertension

OR presence of other risk modifiers: 1

• hs-CRP ≥2.0 mg/L
• CAC >0 AU
• Family history of premature CAD
• Lp(a) ≥50 mg/dL (100 nmol/L)

High-Risk (FRS ≥20%)

• Statin therapy is strongly recommended 1, 3, 2
• Target LDL-C <2.0 mmol/L (approximately 77 mg/dL) 1, 2
• High-intensity statin therapy should be initiated 3, 2

Role of Coronary Artery Calcium Scoring

CAC scoring is strongly indicated for asymptomatic adults ≥40 years with intermediate risk (FRS 10-20%) when treatment decisions are unclear 1:

CAC = 0

• Withholding statin therapy is reasonable 1
• Reassess within 5 years for patients >40 years 1
• Exceptions (still consider treatment): 1
  • Smoking
  • Diabetes
  • Uncontrolled hypertension
  • Genetic dyslipidemias
  • Prominent family history of premature ASCVD

CAC 1-99

• Individual decision-making is necessary as risk remains intermediate 1
• Consider patient preferences, additional risk factors, and willingness to take long-term therapy 1

CAC >100

• Pharmacotherapy is reasonable regardless of FRS 1
• This threshold upgrades risk classification and supports statin initiation 1

Treatment Targets and Monitoring

Primary Lipid Targets

LDL-C is the primary treatment target 1:

• Optimal LDL-C: ≤2.0 mmol/L (approximately 77 mg/dL) 1
• High-risk patients (FRS ≥20%): <2.0 mmol/L 1, 2
• Intermediate-risk patients (FRS 10-19%): <3.5 mmol/L 1
• Low-risk patients (FRS <10%): <5.0 mmol/L 1

Alternative Treatment Targets

Non-HDL-C and ApoB are considered strong alternative targets 1:

• Non-HDL-C: ≤2.6 mmol/L 1
• ApoB: ≤80 mg/dL 1

Add-On Therapy

For patients not reaching targets with statin therapy alone 1:

• Ezetimibe is recommended as first-line add-on therapy 1
• Bile acid sequestrants are an alternative, though evidence is less conclusive 1
• Discuss reduction in CVD risk versus cost/access and side effects with the patient 1

Reassessment Schedule

Risk screening should be repeated every 5 years for men and women aged 40-75 years 1:

• This applies to both initial risk assessment and CAC rescreening when indicated 1
• Risk assessment should also be completed whenever a patient's expected risk status changes 1

Important Clinical Caveats

FRS Limitations in Canadian Context

The FRS may overestimate risk in contemporary Canadian populations 4, 5:

• A 2022 study found FRS overestimated risk by 109% in women and 131% in men before recalibration 5
• After recalibration using Ontario population data, overestimation was reduced to 49% in women and 32% in men 5
• This overestimation could lead to unnecessary statin prescriptions in up to 26 per 1,000 low-risk women and 80 per 1,000 low-risk men 5

Modified FRS for Family History

The CCS recommends doubling the FRS estimate when there is a family history of premature CVD 1:

• This "modified FRS" accounts for the 2-fold increased risk associated with family history 1
• Family history is defined as premature ASCVD in first-degree relatives 1

Performance Gaps in Canadian Practice

A 2017 systematic review revealed substantial gaps in cardiovascular risk factor management in Canada 6:

• Dyslipidemia awareness (42.7%), treatment (40.9%), and control (41.5%) rates were all suboptimal 6
• These rates were notably worse than hypertension management, where awareness (84.3%) and treatment (82.0%) were above target 6
• This suggests significant room for improvement in implementing lipid management guidelines 6

Age-Related Considerations

The FRS has limited utility in younger adults (<40 years) and may not adequately estimate risk 1:

• The Framingham study included few data from patients younger than 40 years 1
• In men aged 18-39 years, FRS remained <10% even in those with substantial risk factor burden 7
• For younger patients with ED or other early markers of vascular disease, consider cardiovascular risk independently of FRS 1