Maxime Verhoeven

162 Chapter 8 market in 2015, the mean purchase price of etanercept for Dutch hospitals decreased almost 60%, reducing the price difference between etanercept and its biosimilar. 4 As mentioned above, the study of Müskens et al. only analysing cost that are relevant for a certain budget, is classified as a budget impact analysis. For a more comprehensive evaluation of treatment strategies, health-economic studies are more appropriate. Depending on which costs and outcomes are taken into account in the analysis, an economic evaluation can be classified as a cost effectiveness (weighing costs against a disease specific health outcome), cost-utility (weighing costs against a general quality of life ‘utility’ measure, i.e., quality adjusted life years, QALYs), cost-minimization (only analyzing cost, assuming equal effectiveness and similar populations, which condition was not met in the study of Müskens) or cost-benefit (expressing health outcomes also in monetary value, leading to a net-monetary effect) analysis. Health-economic studies of medication strategies often are cost effectiveness or cost-utility analyses. In all analyses, key decisions are on which costs specifically to include. First, costs within the health care sector, i.e., related to intervention, not only cost of medication, but also e.g., of intravenous administration, 3 testing for latent tuberculosis, physician visits and consultations and admissions. 6 Second, patient and family costs, occurring outside of health care system, like care provided by family members, and transportation. 6 Third, costs in other sectors, e.g., related to loss of productivity, due to work disability, absenteeism (time missed from work due to health reasons) and presenteeism (impaired performance while at work due to health reasons resulting in productivity loss). 6,7 This last cost category is often referred to as indirect cost. Cost of work disability can be estimated applying the human capital method, taking into account productivity loss over the whole period of the potential working life, and by the friction-cost method. Then, only the average time-span the employing organisation needs to restore the initial production level is taken into account. 6 Next, the choice of the measure of effectiveness is of interest. This may be a unidimensional and disease specific health outcome, e.g., the percentage of patients achieving remission, but also a multidimensional, generic health outcome, such as QALY. Generic health outcomes enable comparisons of study outcomes of studies evaluation quite different interventions. 6 If Müskens et al. would have performed a longer-term study with a wider scope, also looking at indirect cost, this study might have had a positive result, e.g., because a higher percentage of RA patients using a bDMARD could have translated into higher quality of life of patients and less productivity losses. Who’s looking: interests and interpretations of specific stakeholders Interpretations of whether an expensive medication or novel therapeutic strategy is “worth it” depend not only on the methodology used, i.e., costs and outcomes assessed,