In a randomized controlled trial comparing a new antihypertensive drug versus placebo, the incidence of stroke in the treatment group was 2% and in the placebo group was 5%. What is the Number Needed to Treat (NNT)?
- A 33 ✓
- B 20
- C 50
- D 3
Correct answer: A. 33
Explanation
Absolute Risk Reduction (ARR) = Risk in control group − Risk in treatment group = 5% − 2% = 3% = 0.03. NNT = 1/ARR = 1/0.03 ≈ 33. NNT represents the number of patients who need to be treated to prevent one additional adverse event. A lower NNT indicates greater therapeutic benefit.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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