Steps in implementing a health economic evaluation.

Within the health technology assessment framework,1 an economic evaluation compares health technologies in terms of their costs, clinical effectiveness, side effects, impact on health-related quality of life and impact on organisations. It involves the choice of the ‘best alternative’ to which a (new) technology is compared, the comparison of the benefits and consequences between strategies balanced against the difference in costs and the choice of the economic perspective. This article presents an introduction to steps to implementing a health economic evaluation, based on the health economics literature2 and guiding principles such as the Consolidated Health Economic Evaluation Reporting Standards statement, which has been proposed3 to standardise the conduct and reporting of health economic evaluations, with examples specific to rheumatic diseases. An economic comparative assessment requires an explicit statement of the broader context for the study, and a description of the disease in question. This includes justification for choices to be made, the values important to guide the judgement of decision makers and its relevance for health policy or clinical practice decisions. ### Trial-based economic evaluation Cost–effectiveness analyses compare new technologies, such as a drug treatment or an orthopaedic surgery, with standard care, by calculating associated health effects and costs, at best using data from a randomised clinical trial. The incremental cost–effectiveness ratio (ICER) is routinely used to express the cost–effectiveness of one treatment over another in the form of a ratio, as costs per health effect gained. ICER = Cost of new treatment– Cost of standard care Effectiveness of new treatment– Effectiveness of standard care –––––––––––––––––––––––––––––––––––––––––––– As such, the ICER provides the cost of an additional unit of health (eg, days with pain relief, reduced level of disability, fracture avoided) gained when substituting the old with the new technology. The ICER is best explained on the cost–effectiveness plane (figure 1) where …