1LDL Statin Targets — AHA/ACC 2019 Guidelines
| Risk Stratification Category | LDL Target (mg/dL) | LDL Target (mmol/L) | Recommended Statin Intensity |
|---|---|---|---|
| Very High Risk (Established ASCVD, DM + major risk factors, or severe FH) | < 55 mg/dL | < 1.4 mmol/L | High-intensity statin + Ezetimibe ± PCSK9 inhibitor |
| High Risk (10-year ASCVD risk ≥ 20%, or Diabetes aged 40–75) | < 70 mg/dL | < 1.8 mmol/L | High-intensity statin (Aim for ≥50% LDL reduction) |
| Intermediate Risk (10-year ASCVD risk 7.5% – 19.9%) | < 100 mg/dL | < 2.6 mmol/L | Moderate-intensity statin (Aim for 30%–49% reduction) |
| Low Risk (<7.5% 10-year ASCVD risk, baseline LDL <190) | < 130 mg/dL | < 3.4 mmol/L | Lifestyle optimization; consider statin if LDL ≥ 160 mg/dL |
| Severe Hypercholesterolaemia (Primary LDL ≥ 190 mg/dL) | < 100 mg/dL (<70 if ASCVD) | < 2.6 mmol/L | High-intensity statin without requiring risk estimation |
2When the Friedewald Formula is Inaccurate
- Triglycerides > 400 mg/dL (4.5 mmol/L): The assumption of a fixed 5:1 ratio of TG to VLDL-C breaks down. Friedewald substantially underestimates LDL-C. Use direct homogeneous enzymatic LDL measurement.
- Non-Fasting Sample: Post-prandial chylomicrons carry high triglyceride loads without proportional VLDL-C, falsely suppressing calculated LDL. Request a strict 12-hour fasting panel.
- Type III Hyperlipoproteinaemia (Dysbetalipoproteinaemia): Accumulation of cholesterol-rich beta-VLDL remnants invalidates the TG/5 factor. Direct LDL is mandatory.
- Very Low LDL-C (<70 mg/dL / 1.8 mmol/L): In patients on PCSK9 inhibitors or intensive statins, Friedewald can yield negative or falsely depressed numbers. The Martin-Hopkins or direct assay is preferred.
3High-Intensity Statin Options in Clinical Practice
- Atorvastatin 40–80 mg once daily: Reduces LDL-C by 49%–60%. The workhorse generic high-intensity agent across Indian hospital formularies.
- Rosuvastatin 20–40 mg once daily: Reduces LDL-C by 52%–63%. Hydrophilic with minimal CYP3A4 metabolism; lower doses (10–20 mg) often achieve equivalent efficacy in South Asian populations.
- Ezetimibe 10 mg once daily (Add-on): Blocks NPC1L1 intestinal cholesterol absorption, yielding an additional 15%–20% LDL reduction on top of statins (IMPROVE-IT trial). First-line add-on when targets are missed.
- PCSK9 Inhibitors (Evolocumab / Alirocumab): Subcutaneous monoclonal antibodies delivering 50%–60% additional reduction. Reserved for familial hypercholesterolaemia or post-ACS patients resistant to statin + ezetimibe.
4Frequently Asked Questions
What is the Friedewald formula for LDL?+
LDL cholesterol (mg/dL) = Total Cholesterol − HDL − (Triglycerides ÷ 5). In SI units: LDL (mmol/L) = Total Cholesterol − HDL − (Triglycerides ÷ 2.2). It operates on the principle that nearly all triglycerides in a fasting state are contained in VLDL, which carries cholesterol in an approximate 5:1 ratio.
What is non-HDL cholesterol and why is it superior in diabetes?+
Non-HDL cholesterol (Total Cholesterol minus HDL) measures all circulating atherogenic particles containing apolipoprotein B, including remnant lipoproteins and VLDL. In diabetic dyslipidaemia and hypertriglyceridaemia, LDL particles are small and dense; non-HDL captures the true atherogenic particle burden far better than calculated LDL alone.
What is the 'Rule of 6' in statin dosing?+
The Rule of 6 states that doubling the dose of any given statin produces only an incremental 6% further reduction in LDL-C (e.g., Atorvastatin 20 mg reduces LDL by ~43%, while 40 mg reduces it by ~49%). If a patient remains far from goal, adding ezetimibe 10 mg (which gives an extra 15%–20% reduction) is clinically superior to simply doubling statin doses.
Medical Disclaimer: This clinical calculator is designed for healthcare professionals. Friedewald LDL-C estimation is valid only in fasting patients with triglycerides <400 mg/dL. Statin initiation and intensification should incorporate clinical cardiovascular risk, coronary artery calcium (CAC) scores, and shared clinical decision-making.