Analysis, sample size, and power for estimating incremental net health benefit from clinical trial data

Stinnett and Mullahy recently introduced the concept of net health benefit as an alternative to cost-effectiveness ratios for the statistical analysis of patient-level data on the costs and health effects of competing interventions. Net health benefit addresses a number of problems associated with cost-effectiveness ratios by assuming a value for the willingness-to-pay for a unit of effectiveness. We extend the concept of net health benefit to demonstrate that standard statistical procedures can be used for the analysis, power, and sample size determinations of cost-effectiveness data. We also show that by varying the value of the willingness-to-pay, the point estimate and confidence interval for the incremental cost-effectiveness ratio can be determined. An example is provided.