A drug company-sponsored RCT shows a drug reduces cardiovascular events by 2% in absolute terms (from 4% to 2%), but the relative risk reduction is reported as 50%. The primary critique of presenting only relative risk reduction is that it:
- A Ignores the baseline risk and can mislead clinical decision-making ✓
- B Overestimates the number needed to treat
- C Is mathematically incorrect
- D Eliminates confounding by baseline risk
Correct answer: A. Ignores the baseline risk and can mislead clinical decision-making
Explanation
Relative risk reduction (RRR) = (Rc−Re)/Rc = (0.04−0.02)/0.04 = 50%, which sounds impressive. However, the absolute risk reduction (ARR) = Rc−Re = 2%, and NNT = 1/ARR = 50 — meaning 50 patients must be treated for one additional benefit. When the baseline risk is low, even a 50% RRR may translate to a very large NNT, making the clinical utility modest. Presenting only RRR inflates perceived benefit by ignoring baseline risk.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.