A Basic Approach to Select the Appropriate Method in case of Extended Dominance

Objective: In cost-effectiveness analysis, treatment methods are ranked by cost and effectiveness, and a method more costly but less effective, is dominated. In models that none of the methods is absolutely dominated but one of them is extendedly dominated, selecting cost-effective method is complicated. Aim of this study was to propose a classification for magnitude of incremental cost-effectiveness ratio of extendedly dominated method, which can use for deciding about cost-effectiveness of this treatment. Methods: Simulated data based on actual data, and simulated hypothetical data in accordance with actual data were used. All possibilities were tried to consider by generating different costs, effectiveness and response rates. Proportional magnitudes of incremental cost-effectiveness ratios of treatments extendedly dominated were investigated. Descriptive statistics for each model, and weighted means by response rates were calculated and change in percentage of extended dominance were compared. Results: Magnitude of incremental cost-effectiveness ratio of the method extendedly dominated is a quite important factor for deciding about it, when response rates of alternative methods are similar or same. Slight changes were observed as the response rates differ from each other, but there was not an extreme impact on proportions of extended dominance. Conclusion: A very simple and practical classification which can be used to assess the proportional magnitude of the incremental cost-effectiveness ratio of extendedly dominated treatment method and be valid regardless of whether response rates of treatments in model are same or different was suggested