Background: Systematic reviews play an important role in improving understanding of the comparative effectiveness of medical interventions, but economic data have not usually been included despite their importance in determining the value of interventions. This paper addresses the usefulness of incorporating economic evaluation data into systematic reviews of medical interventions.
Methods: A consensus process including outside experts was used to develop a conceptual framework for including economic evidence alongside systematic reviews, and to define tradeoffs in presenting economic data. The framework was based on five questions: (1) Why are stakeholders interested in economic evaluation data? (2) When should economic evaluation data be requested in a systematic review? (3) Who is interested in economic evaluation data? (4) What economic evidence is of interest? and (5) How should the economic evaluation be conducted?
Results: Decisions about inclusion of economic data in systematic reviews should be based on the magnitude of the incremental cost, magnitude of the incremental effect, and the probability that economic evidence will change a decision. Economic data should be given a high priority when evidence indicates a small effect at a high level of expenditure with a high probability of influencing a decision. All stakeholders (including public and private insurers) should be interested in economic data and the perspectives of patients, providers, and manufacturers because patients and providers together determine the demand for care and manufacturers determine the supply. Economic data are of interest for decisions at many levels, including decisions about approval and monitoring of services, formulary inclusion, insurance coverage, reimbursement rate, preferred practice guideline, technology adoption or nonadoption, or clinical management. Economic data of interest include information that contributes directly to cost-effectiveness analyses, as well as data on productivity changes related to a disease or its treatment, basic price data, and data on responses to price changes. When it is appropriate to include economic data in a systematic review, it may be sufficient to review available economic analyses, but it may be necessary to perform a new economic evaluation if previous evaluations are inadequate (absent, low quality, or very heterogeneous) or if important new data are available.
Conclusion: The approach to gathering economic data alongside a systematic review of evidence will be governed by the decision context and the need for a new economic evaluation consistent with the other findings of the systematic review.