An economic approach to health care

Economic analyses have the potential to put all of the positive and negative outcomes of an intervention into perspective to aid decision making. The quality of the data upon which the analysis is based has an impact on the resulting quality of the analysis itself. Analysis of cost-effectiveness requires the input of many types of data, and where data are not available, assumptions must be made. There are many instances where the analysis may go wrong, and it is important to remain cognizant of these. The critical parts of the analysis, which have also been identified in quality assessment tools, include the following: design of the study question, sources of probability estimates and cost data, sensitivity analysis, and the interpretation of results. If the readers are able to identify the assumptions of the analysis they are better equipped to judge the validity. We have reviewed economic analyses relating to two hot economic topics in rheumatology. These are the cost-effectiveness of cyclooxygenase-2 (COX-2) inhibitors for 'arthritis' and cost-effectiveness of anti-tumor necrosis factor alpha (anti-TNF) agents for rheumatoid arthritis (RA). The results of the COX-2 analyses vary by review. Some show cost savings, while others calculate a significant cost in order to achieve any change in quality of life. Given the unanswered questions that still exist, it seems reasonable to conclude that COX-2 inhibitors may be cost effective when used in patients at a high risk of GI complications. Unanswered questions remain regarding the concomitant use of low-dose ASA and proton pump inhibitors and how they may affect the results of these economic analyses. The cost-effectiveness of anti-TNF agents has not been explored in as much detail as that of the COX-2 agents. Two studies have presented cost-effectiveness models that include a hypothetical biologic agent. Two economic analyses report on the cost-effectiveness of etanercept compared with traditional disease-modifying anti-rheumatic drugs (DMARDs) in methotrexate-resistant and methotrexate-naïve patients with RA. Both the analyses show that etanercept has a cost-effectiveness ratio of around US$40 000 for every patient who achieves an American College of Rheumatology 20% improvement score (ACR 20) within a 6-month period. A cost-utility analysis was published regarding the use of infliximab in methotrexate resistant RA. It showed a cost-utility ratio of 3400:34 000 Euro per quality adjusted life year (QALY) gained, depending on the country evaluated (Sweden and the UK, respectively). An important finding in all three studies was that indirect costs dominate costs in RA; therefore, they should be included in all future analyses of this disease.