In a study on malaria treatment, the NNT (Number Needed to Treat) is calculated. In the control group 40% develop severe malaria; in the treatment group 20% develop severe malaria. What is the NNT?

• A 2
• B 4
• C 10
• D 5 ✓

Explanation

ARR (Absolute Risk Reduction) = Control Event Rate − Treatment Event Rate = 0.40 − 0.20 = 0.20. NNT = 1 / ARR = 1 / 0.20 = 5. This means 5 patients need to be treated to prevent one additional case of severe malaria. A smaller NNT reflects a more effective treatment; NNT applies to a specific time horizon and population.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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