Adjusting the number needed to treat: incorporating adjustments for the utility and timing of benefits and harms.

The number needed to treat is a unique and cognitively useful summary measurement for the description of medical treatments. However, the original concept lacks the means to account for multiple benefits and harms or differences in the utilities or timings of patient outcomes. The authors describe an "adjusted" number needed to treat that allows for the inclusion of multiple harms and benefits, and also adjustments for the utilities and timings of these outcomes. The expanded version offers a richer description of medical outcomes, and may be utilized as an adjunct to traditional risk-benefit, cost-effectiveness, and decision-analytic techniques.