The cost-of-illness and burden-of-disease of treatment-resistant depression in Austria.

Background: Treatment-resistant depression (TRD) in major depressive disorder (MDD) is most commonly defined as the failure to respond to at least two antidepressant (AD) treatments of adequate duration and adherence. While the health care utilization (RU) and costs of patients with MDD are well documented, little is known about patients with TRD. Therefore, the aim of this study was to determine the direct medical RU of complex therapy pathways and to analyze the total cost-of-illness and the burden-of-disease in Austria.

Methods: In order to quantify the cost-of-illness and burden-of-disease of TRD, the analysis was designed with two steps. First, RU data were collected through an extensive survey of Austrian experts and a systematic literature review. Second, direct, indirect, and intangible costs were calculated using the micro-costing method. The results are presented per patient and based on a patient flow for the entire cohort of TRD patients.

Results: In Austria, the derived prevalence of TRD is 43,732 patients or 583 per 100,000 population. For 2021, the annual direct costs of TRD were estimated at 345.0 million €. At 684.7 million €, the estimated indirect costs were higher than the direct costs, representing 66.5% of the total cost-of-illness. The average annual cost per TRD patient is 23,547 €, of which direct costs are 7,890 €. Adding the years lived with a disability to the years lost due to premature death attributed to TRD resulted in a total of 29,884 disability-adjusted life years (DALYs) for the Austrian society.

Conclusion: Although TRD accounts for only 0.7% (range: 0.6%-1%) of the total health care budget, it represents a significant burden-of-disease. In addition, TRD is associated with a high level of lost productivity in the Austrian economy. These findings support efforts to prioritize TRD as a focus area to achieve health-related goals.