Number Needed to Treat (NNT)
The number of patients who need to be treated with a drug for one additional patient to benefit compared to the control group. A lower NNT indicates greater treatment effectiveness. NNT provides a clinically intuitive measure of drug benefit that complements statistical significance.
Technical Context
NNT = 1 / absolute risk reduction. Example: if a GLP-1 RA reduces 3-year MACE rate from 8.0% (placebo) to 6.4% (treatment), ARR = 1.6%, NNT = 1/0.016 = 63. This means 63 patients must be treated for 3 years to prevent one MACE event. NNT is time-dependent and condition-specific. Lower NNTs indicate greater treatment benefit. NNT for achieving ≥5% weight loss with semaglutide 2.4mg is approximately 1.3-1.5 (almost every treated patient achieves this threshold), reflecting the large treatment effect. NNT should be balanced against number needed to harm (NNH) for key adverse events to assess overall benefit-risk.