Trends in Author-Reported Cost-Effectiveness Thresholds in the United States from 1995 to 2018: Implications for Discount Rates
Bibliographic record
Abstract
BACKGROUND: Decisions based on cost-effectiveness analyses (CEAs) using equal discount rates for health and cost outcomes are consistent with using a constant cost-effectiveness threshold over time. We sought to analyze trends in author-reported cost per quality-adjusted life-year (QALY) thresholds from CEAs published for the US setting over 24 y to retrospectively assess whether the recommended equal discount rates for costs and health were consistent with trends in the CEA literature. METHODS: We used the Tufts CEA Registry to assess whether author-reported cost-effectiveness thresholds changed in CEAs published for the US setting between 1995 and 2018 and back-calculated the implied discount rate for health based on these trends for inflation-adjusted cost-effectiveness thresholds and an annual discount rate for costs of 3%. RESULTS: We found 1995 CEAs published for the US setting and found that average nominal and inflation-adjusted cost-effectiveness thresholds increased over that time period. The discount rate for health would need to equal 2.43% to 2.48% (depending on the subset of CEAs analyzed) to be consistent with the observed trends in inflation-adjusted author-reported cost-effectiveness thresholds. We also found that restricting our analysis to currency years between 1995 and 2014 would result in a back-calculated discount rate for health of 2.99% to 3.28%. CONCLUSIONS: We found that CEA researchers have implicitly assumed that inflation-adjusted cost-effectiveness thresholds in the United States have been increasing over time (1995-2018), which is inconsistent with the recommended and prevailing choice of equal discount rates for health and cost outcomes. Our results are sensitive to the cutoff year used in the analysis. HIGHLIGHTS: 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).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.055 | 0.321 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.007 | 0.010 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".