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 (‘k’). Such estimates are needed to inform the net health impact of funding decisions. We map policy thresholds in HTA guidelines against published estimates of k. 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 k 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 k were available for 13 countries. Among the eight countries with explicit policy thresholds and k estimates, three matched. The recommended perspective influences whether k alone is sufficient or appropriate to inform cost-effectiveness judgements. It is important that guideline setters are aware of empirical estimates of k; and that economic evaluations consider k to reflect health opportunity costs even where the policy threshold is justified on other grounds.