Analysis sans frontières: can we ever make economic evaluations generalisable across jurisdictions?

Over the last decade or so, a number of healthcare systems have used economic evaluations as a formal input into decisions about the coverage or reimbursement of new healthcare interventions. This change in the policy landscape has placed some important demands on the design and characteristics of economic evaluation and these are increasingly evident in studies being presented to decision makers. One challenge has been to make studies specific to the context in which the decision is being taken. This is because of the inevitable geographical variation in many of the parameters within an analysis. There has been a series of important contributions to the published literature in recent years on how to quantify geographical heterogeneity within economic analyses based on randomised controlled trials. However, there are good reasons for economic evaluation for decision making to be undertaken using methods of evidence synthesis and decision analytical modelling, but issues of geographical variation still need to be handled appropriately. The key requirements of economic evaluations for decision making within healthcare systems can be defined as follows: (i) a design that meets the objectives and constraints of the healthcare system; (ii) coherent and complete specification of the decision problem; (iii) inclusion of all relevant evidence; and (iv) recognition and appropriate handling of uncertainty. In satisfying these requirements, it is important to be aware of variation between jurisdictions, and this imposes some important analytical requirements on economic studies. While many agencies have produced guidelines on preferred methods for healthcare economic evaluation, these exhibit considerable variation. Some of this variation can be justified by genuine differences between systems in clinical practice, objectives and constraints, while some of the variation relates to differences of opinion about appropriate analysis given methodological uncertainty. However, some of the variation in guidance is difficult to justify and is inconsistent with the aims and objectives of the systems the analyses are seeking to inform. Decision makers and analysts need to work together to streamline and where possible harmonise guidelines on methods for economic evaluations, whilst recognising legitimate variation in the needs of different healthcare systems. Otherwise, there is the risk that scarce resources will be wasted in producing country-specific analyses in situations where these are not justified. Expected value of information analyses are also emerging as a tool that could be considered by decision makers to guide their policy on the acceptance or non-acceptance of data from other jurisdictions.