When future change matters: modelling future price and diffusion in health technology assessments of medical devices

Objectives: Whilst health technology assessments (HTAs) that take account of future price change have been examined in the literature, the important issue of price reductions that are generated by the reimbursement decision has been ignored. Our objective is to explore the impact of future price reductions caused by increasing uptake on HTAs and decision making for medical devices. Methods: We demonstrate the use of a two-stage modelling approach to derive estimates of technology price as a consequence of changes in technology uptake over future periods based on existing theory and supported by empirical studies. We explore the impact on cost-effectiveness and expected value of information analysis in an illustrative example based on a technology used in pre-term birth screening that is in development. Results: The application of our approach to the case study technology generates smaller incremental cost-effectiveness ratios (ICERs) compared to the commonly used single cohort approach. The extent of this reduction of the ICER depends on the magnitude of the modelled price reduction, the speed of diffusion and the length of the assumed technology-life horizon. Results of value of information analysis are affected through changes in the expected net benefit calculation, the addition of uncertain parameters and the diffusion-adjusted estimate of the affected patient population. Conclusions: Since modelling future changes in price and uptake has the potential to affect HTA outcomes, modelling techniques that can address such changes should be considered for medical devices that may otherwise be rejected.