NNT

Also known as: Number Needed to Treat

The number of patients to treat to prevent one adverse outcome.

Definition

Number Needed to Treat (NNT) = 1 / absolute risk reduction. It expresses clinical benefit in patient-relevant terms. NNT=10 means treating 10 patients prevents one event. Lower NNTs indicate stronger effects. Used heavily in NICE / ICER cost-effectiveness analyses.

See also

• QALY — A measure combining length and quality of life used in cost-effectiveness analysis.

Other clinical terms

• Phase 1 trial
• Phase 2 trial
• Phase 3 trial
• Primary endpoint
• Surrogate endpoint
• CDx