Numbers-needed-to-treat analysis: An explanation using antipsychotic trials in schizophrenia

Abstract

The evaluation of treatment effects is important to both the clinician and the patient. However, outcomes in randomised trials are often difficult to apply to the clinic. The number needed to treat (NNT) is one method that facilitates the interpretation of clinical trials in a meaningful way. When combined with the number needed to harm (NNH), the balance between the risks and benefits of a particular treatment can be appreciated. We illustrate the use of these concepts by focusing on recent large pragmatic studies of antipsychotics, including CATIE, EUFEST and CUtLASS.