number needed to harm


number needed to harm

The cohort of patients who must receive a specified medication in routine therapeutic use a specified adverse outcome. In the context in which the term is used, 'adverse outcome' means death or significant impairment or disability that is attributable to the specified medication.

number needed to harm

The number of patients needed to be exposed to a noxious agent or medical intervention in order that one might suffer an adverse event. This concept is important in the assessment of the relative hazard of medical interventions, the relative toxicities of poisons, or the relative value of certain experimental interventions. Generally, the smaller the value, the more dangerous the therapy or noxious agent.