number needed to treat
Also written as: NNT — number needed to treat
A statistical measure indicating how many patients must receive a specific treatment for one patient to benefit, commonly used to evaluate the effectiveness of preventive cardiology interventions.
Full Definition
Number needed to treat (NNT) is an epidemiological measure that represents the average number of patients who need to be treated with a specific intervention for one additional patient to achieve a beneficial outcome compared to a control treatment. In preventive cardiology, NNT is frequently used to communicate the effectiveness of interventions such as statin therapy, antihypertensive medications, or lifestyle modifications. For example, an NNT of 50 for statin therapy means that 50 patients must be treated for 5 years to prevent one cardiovascular event. Lower NNT values indicate more effective interventions, with NNT values below 10 generally considered highly effective.
Usage
Usage note: NNT should be accompanied by the time frame and specific outcome when reported; use lowercase for the spelled-out form.
In Context
- "The number needed to treat with high-intensity statin therapy is 39 patients over 5 years to prevent one major cardiovascular event." — clinical evidence review
- "When counseling patients, explain that the number needed to treat helps quantify the likelihood of personal benefit from therapy." — patient counseling guideline