Trends in Author-Reported Cost-Effectiveness Thresholds in the United States from 1995 to 2018: Implications for Discount Rates.

We show visually and through equations that the recommended and prevailing practice of using equal discount rates for cost and health outcomes in cost-effectiveness analyses (CEAs) logically implies a constant inflation-adjusted cost-effectiveness threshold over time.Using data from the Tufts CEA Registry, we found that author-reported cost-effectiveness thresholds used in CEAs published for the US setting with currency years between 1995 and 2018 increased over time (both with and without adjustment for inflation).Assuming an annual discount rate for costs equal to 3%, the discount rate for health would need to equal approximately 2.5% to preserve consistency across decisions taken at different dates given the observed trends in inflation-adjusted author-reported cost-effectiveness thresholds.This finding depends on the cutoff year used in the analysis (data from currency years 1995-2014 would support use of equal discount rates, whereas data after 2014 would suggest a sharper trend toward increasing cost-effectiveness thresholds).