Synonyms
NNH
Definition
Number needed to harm (NNH) is a clinically useful measure for the difference between treatment groups regarding a negative outcome, such as all-cause discontinuation, relapse, or number of patients with significant weight gain. It denotes the number of patients that need to be exposed to a treatment until one additional negative event of interest occurs in excess of the rate in the comparator group. The NNH is computed as 1/(percent rate of the active treatment group - percent rate of the comparator group). An NNH of below 10 is generally considered clinically meaningful.
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(2015). Number Needed to Harm. In: Stolerman, I.P., Price, L.H. (eds) Encyclopedia of Psychopharmacology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-36172-2_200774
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DOI: https://doi.org/10.1007/978-3-642-36172-2_200774
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Publisher Name: Springer, Berlin, Heidelberg
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