Avaliação Crítica de um Estudo de Avaliação Económica (Parte II): Estudos de Custo-Efectividade e Custo-Utilidade

Abstract

Cost-effectiveness and cost-utility analyses are types of full economic evaluations, simultaneously informing on costs and outcomes of different alternatives. In cost-effectiveness analyses, health outcomes are expressed in natural effectiveness units (e.g., life years gained). In these studies, comparison of two or more alternatives is based on incremental cost-effectiveness ratios (ICER) (ratio of the (i) difference between average/expected costs for each alternative, and the (ii) difference between the average/expected effectiveness of each alternative) – an alternative is considered to be cost-effective when its ICER is lower than the defined willingness-to-pay threshold. On the other hand, in cost-utility analyses, health outcomes are expressed in effectiveness units adjusted for individual or societal preferences. Therefore, in these studies, outcomes are frequently expressed as quality-adjusted life years (QALYs). In fact, QALYs simultaneously incorporate information on the average/expected life expectancy and quality of life following an intervention. In cost-utility analyses, comparison of different alternatives is based on incremental costutility ratios, with calculation and interpretation similar to those of ICER.