In a clinical trial, statin therapy reduces 5-year cardiovascular death from 8% (placebo) to 5% (statin). The Number Needed to Treat (NNT) to prevent one cardiovascular death over 5 years is:
- A 13
- B 20
- C 33 ✓
- D 8
Correct answer: C. 33
Explanation
Absolute Risk Reduction (ARR) = 8% − 5% = 3% = 0.03. NNT = 1/ARR = 1/0.03 = 33.3 ≈ 33. This means 33 patients need to be treated with statins for 5 years to prevent one cardiovascular death. The relative risk reduction = (8−5)/8 = 37.5%, but NNT based on ARR is more clinically useful as it accounts for baseline risk.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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