The practice of discounting in economic evaluations of healthcare interventions

Objectives: Discounting of costs in health-related economic evaluation is g enerally regarded as uncontroversial, but there is disagreement about disco unting health benefits. We sought to explore the current recommendations an d practice in health economic evaluations with regard to discounting of cos ts and benefits. Methods: Recommendations for best practice on discounting for health effect s as set out by government agencies, regulatory bodies, learned journals, a nd leading health economics texts were surveyed. A review of a sample of pr imary literature on health economic evaluations was undertaken to ascertain the actual current practice on discounting health effects and costs. Results: All of the official sources recommended a positive discount rate f or both health effects and costs, and most recommended a specific rate (ran ge, 1% to 8%). The most frequently specified rates were 3% and 5%. A total of 147 studies were reviewed; most of these used a discount rate for health of either 0% (n = 50) or 5% (n = 67). Over 90% of studies used the same di scount rate for both health and cost. While 28% used a zero rate for both h ealth and cost, in 64% a nonzero rate was used for both. Studies where the health measure was in natural clinical units (direct) were significantly mo re likely to have a zero discount rate. Conclusion: The finding that 28% of studies did not discount costs or benef its is surprising and concerning. A lower likelihood of discounting for ben efits when they are in natural units may indicate confusion regarding the r ationale for discounting health effects.