Using economic evaluations to reduce the burden of asthma and chronic obstructive pulmonary disease.

There is increasing interest in the use of economic evaluations in healthcare, because of the need to maximise health benefits from limited resources. The focus of most economic evaluations is on efficiency, though they may also consider the issue of equity. In an economic evaluation, it is important to consider all the relevant costs, not just the acquisition cost of the treatment. Likewise, it is important to include all the benefits in the economic appraisal, although the outcomes of relevance to decision-makers may differ according to their perspective. If an intervention costs less but delivers fewer benefits than the comparator or, more commonly, a new intervention increases benefits compared with standard therapy but at increased cost, decision-makers must consider whether the extra cost is worth the extra benefit. This depends on the opportunity cost of introducing the new intervention - i.e. the benefit forgone by doing less of something else to fund it. In other words, decision-makers need to decide on the maximum amount they are willing to pay for an additional unit of health benefit. The result of an economic evaluation will be strongly influenced by the information used in the analysis. Currently, clinical trials are the most common source of data for economic evaluations. Yet there are a number of limitations in the information generated by clinical trials, which are primarily designed for regulatory approval. Consequently, decision analytical models are being increasingly used to synthesise data from various sources and to manage uncertainty in input parameters. When using economic evaluations, decision-makers may be unwilling to take a broad perspective on costs, focusing instead on their narrow budgetary concerns. Incentives may be required within healthcare systems to ensure that decision-makers adhere more strictly to the results of formal analysis.