Number needed to treat: What it is and what it isn't, and why every clinician should know how to calculate it

Abstract

NNT and NNH provide a means for every clinician to rapidly calculate the relevance of a clinical trial result, provided these results are presented as a binary outcome (ie, absence or presence of response, remission, relapse, clinically relevant weight gain, sedation, akathisia, and others). The P value does not answer the question of how clinically important the result is. Calculating the NNT or NNH of a statistically significant result can help put that result into clinical perspective. © Copyright 2011 Physicians Postgraduate Press, Inc.