Extract
S. Lettis and O. Keene raise questions about my paper on some misleading uses of the number needed to treat (NNT) for study outcomes such as chronic obstructive pulmonary disease (COPD) exacerbations. Certainly, when dealing with recurrent events such as exacerbations, it is statistically more informative to analyse all events with tools such as incidence rates, rate ratios and rate differences. However, some critical assumptions about the rates are essential to obtain valid estimates of these measures and, consequently, a valid estimate of the NNT.
Abstract
“Event-based” numbers needed to treat, such as those from the TORCH trial, should be used with extreme caution http://ow.ly/U31OH
Footnotes
Conflict of interest: Disclosures can be found alongside the online version of this article at erj.ersjournals.com
- Received August 31, 2015.
- Accepted September 3, 2015.
- Copyright ©ERS 2016