Letters Section Editor: Robert M. Golub, MD, Senior Editor.
In Reply: We agree with Dr Young that the NNT can be useful for evaluating the effect of an intervention. The NNT is calculated as the reciprocal of the absolute risk reduction and describes the average number of participants who must be treated to prevent 1 occurrence of an event. The NNT is particularly effective when outcomes are discrete events.1 For continuous outcomes, such as those measured in our study, threshold cutoffs for “clinically significant” changes need to be defined. While the use of different thresholds will necessarily result in different NNTs, clinically significant thresholds for the pediatric population are not well established.
Savoye M, Dziura J. Efficacy of a Weight Management Program in Overweight Children—Reply. JAMA. 2007;298(16):1860-1861. doi:10.1001/jama.298.16.1860-b