Critical issues in the economic evaluation of interventions against communicable diseases.

Economic appraisal seeks to provide policy-makers with guidance about how scarce resources can be used to derive the greatest possible social benefit. Its use in the health sector has increased dramatically over the last decade although much of it has been focused on the problems of the more developed countries. The relatively sparse literature on communicable diseases has been dominated by interventions related to HIV/AIDS, hepatitis, malaria and tropical diseases. Reviews of this literature from the perspective of specific conditions such as Hepatitis B are already available, and recently the entire literature has been evaluated against the technical criteria for economic evaluations published in standard textbooks. Accordingly, this paper focuses on issues which would make economic appraisal more useful to policy-makers than it currently is. Given that few countries have the resources to undertake all the necessary analysis in their own settings, it is important that studies in one setting are undertaken in a way that allow generalisability to similar settings. Some of the most important challenges this poses for cost-effectiveness analysis (CEA) are identified. Firstly, incremental analysis is appropriate to local decision making when policy-makers are constrained to keep the current interventions and can consider only marginal improvements. However, it does not allow re-evaluation of existing interventions and is not transferable across settings. A version of Generalised CEA is proposed as an alternative. Secondly, data on costs and effectiveness are often not presented appropriately. The challenge for effectiveness is to adjust the evidence from efficacy studies to allow for different patient or population groups, and local variations in adherence, coverage, and infrastructure. For costs, it is important for studies to report the physical resources used in an intervention as well as unit prices. Thirdly, some long-term effects are still not well incorporated into CEA, especially those affecting child development and drug resistance. These questions are technically challenging and require more concerted efforts over the next few years. Finally, it is important for analysts to provide decision-makers with estimates of the resources that would be required to implement interventions claimed to be cost-effective. These improvements would better enable the evidence from economic analyses to enter the policy debate and be weighed against the other goals and objectives of the health system when allocating scarce resources.