Cost-effectiveness thresholds in policy and practice: do HTA guidelines align with estimates of health opportunity cost?

Health technology assessment (HTA) processes provide evidence to inform the supply of healthcare, often comparing results from economic evaluation to a policy threshold to judge cost-effectiveness. However, recommended policy thresholds may not always align with empirical estimates of the opportunity costs of health care expenditure, captured by marginal productivity of healthcare expenditure ('<i>k</i>'). Such estimates are needed to inform the net health impact of funding decisions. We map policy thresholds in HTA guidelines against published estimates of <i>k</i>. We extract information from HTA guidelines identified in a previous literature review, including recommended perspective, relevant costs and outcomes, and justification for the threshold. Studies estimating <i>k</i> were obtained from a separate review. Of the 47 included HTA guidelines, 20 state an explicit policy threshold and 12 justify their choice. Estimates of <i>k</i> were available for 13 countries. Among the eight countries with explicit policy thresholds and <i>k</i> estimates, three matched. The recommended perspective influences whether <i>k</i> alone is sufficient or appropriate to inform cost-effectiveness judgements. It is important that guideline setters are aware of empirical estimates of <i>k</i>; and that economic evaluations consider <i>k</i> to reflect health opportunity costs even where the policy threshold is justified on other grounds.