PRM58 - IMPACT OF FUTURE COSTS IN COST-EFFECTIVENESS ANALYSES AND A COMPARISON OF DIRECT AND INDIRECT METHODS USING MODELS OF CABAZITAXEL IN PROSTATE CANCER AND CLOPIDOGREL IN ACUTE CORONARY SYNDROME

The increasing debate on the inclusion of future costs related and unrelated to the disease and non-medical costs in cost-effectiveness analyses has led to questions on the appropriate methodology. Direct and indirect methods have been described by Ekman and Meltzer, respectively, but not compared to date. This work aims to assess their impact on cost-effectiveness based on models of cabazitaxel in prostate cancer and of clopidogrel in reduction of cardiovascular events in Sweden. First, using the direct inclusion method, we modified the clopidogrel six-state Markov model to account for future costs and to analyze their impact on the incremental cost-effectiveness ratio (ICER) based on different mean ages of the cohort. Secondly, we used the cabazitaxel three-state Markov model to apply the direct and the indirect inclusion methods and compare their ICERs. In the clopidogrel model, for the cohort age under 45, the ICER was slightly lower with future costs accounted for than without. Above 45 years of age, as annual consumption net of earning becomes positive, the ICER increases when including future costs and reaches a plateau at age 64 (retirement age in Sweden). For cabazitaxel, with a cohort median age of 68, both direct and indirect methods increased the ICER, by 5% and 24%, respectively. Among patients under 60 years, a lower ICER was observed with the indirect method compared with the direct method. Conversely, the ICER when applying indirect method was higher in those aged above 60 years. These results suggest that the impact of future costs on the ICER depends on the target population age. This further raises ethical concerns about the value of treatments in the elderly population. Further investigation is warranted to assess the reliability of the indirect inclusion method for comparability between studies including future costs and those excluding them.