When should statin (HMG-CoA reductase inhibitor) therapy be initiated?

When to Start Statin Therapy

Statin therapy should be initiated based on ASCVD risk assessment, with specific recommendations for different risk categories including primary prevention for those with diabetes, elevated 10-year ASCVD risk, or high LDL-C levels, and secondary prevention for all patients with established ASCVD. 1, 2

Primary Prevention

Adults with Diabetes

• Initiate moderate-intensity statin therapy in adults 40-75 years with diabetes, regardless of calculated 10-year ASCVD risk 1, 2
• Consider high-intensity statin therapy for adults with diabetes and multiple ASCVD risk factors, especially those aged 50-70 years 1, 2
• For adults 20-39 years with diabetes and additional ASCVD risk factors, consider initiating statin therapy in addition to lifestyle therapy 1, 2

Adults without Diabetes (Based on 10-year ASCVD Risk)

• High Risk (≥20% 10-year ASCVD risk): Initiate high-intensity statin therapy to reduce LDL-C by ≥50% 1, 2
• Intermediate Risk (≥7.5% to <20% 10-year ASCVD risk): Initiate moderate-intensity statin therapy to reduce LDL-C by ≥30% 1, 2
• Borderline Risk (5% to <7.5% 10-year ASCVD risk): Consider moderate-intensity statin therapy if risk-enhancing factors are present 1
• Low Risk (<5% 10-year ASCVD risk): Generally, statin therapy not recommended unless other indications present 1

Adults with Elevated LDL-C

• For adults with LDL-C ≥190 mg/dL (≥4.9 mmol/L), initiate maximally tolerated statin therapy, preferably high-intensity 1, 2

Secondary Prevention

• Initiate high-intensity statin therapy for all patients with established ASCVD (history of MI, stroke, TIA, stable or unstable angina, coronary or other arterial revascularization, or peripheral artery disease) regardless of age 1, 2
• For patients with ASCVD unable to tolerate high-intensity statin, use moderate-intensity statin 1, 2
• For patients with ASCVD considered very high risk, if LDL-C remains ≥70 mg/dL on maximally tolerated statin dose, consider adding ezetimibe or PCSK9 inhibitor 1, 2

Risk Assessment Refinement

• In intermediate-risk or selected borderline-risk adults where decision about statin therapy remains uncertain, consider coronary artery calcium (CAC) score to guide treatment 1, 3:
  • If CAC score is zero: Reasonable to withhold statin therapy and reassess in 5-10 years (unless diabetes, family history of premature CHD, or smoking is present) 1, 3
  • If CAC score is 1-99: Reasonable to initiate statin therapy for patients ≥55 years 1
  • If CAC score is ≥100 or ≥75th percentile: Reasonable to initiate statin therapy 1, 4

Special Populations

Older Adults (>75 years)

• For adults >75 years with established ASCVD: Reasonable to continue statin therapy if already on it 1
• For adults >75 years without established ASCVD: May be reasonable to initiate moderate-intensity statin therapy after discussion of potential benefits and risks 1
• Consider stopping statin therapy when functional decline, multimorbidity, frailty, or reduced life expectancy limits potential benefits 1

Monitoring After Initiation

• Obtain lipid profile at initiation of statin therapy, 4-12 weeks after initiation or dose change, and annually thereafter 1
• Assess adherence to lifestyle changes and medication effects 1

Common Pitfalls to Avoid

• Undertreatment of high-risk patients, particularly those with established ASCVD or diabetes 2, 5
• Overreliance on risk calculators without considering additional risk-enhancing factors 2, 6
• Discontinuing statins due to subjective complaints without attempting rechallenge with different statin 2
• Failure to engage patients in shared decision-making about statin therapy, especially for primary prevention 1