How relevant are social costs in economic evaluations? The case of Alzheimer's disease.

Background: The main objective of this study was to analyse how the inclusion (exclusion) of social costs can alter the results and conclusions of economic evaluations in the field of Alzheimer's disease interventions.

Methods: We designed a systematic review that included economic evaluations in Alzheimer's disease. The search strategy was launched in 2000 and ran until November 2018. The inclusion criteria were: being an original study published in a scientific journal, being an economic evaluation of any intervention related to Alzheimer's disease, including social costs (informal care costs and/or productivity losses), being written in English, using QALYs as an outcome for the incremental cost-utility analysis, and separating the results according to the perspective applied.

Results: It was finally included 27 studies and 55 economic evaluations. Around 11% of economic evaluations changed their main conclusions. More precisely, three of them concluded that the new intervention became cost-effective when the societal perspective was considered, whereas when using just the health care payer perspective, the new intervention did not result in a cost-utility ratio below the threshold considered. Nevertheless, the inclusion of social cost can also influence the results, as 37% of the economic evaluations included became the dominant strategy after including social costs when they were already cost-effective in the health care perspective.

Conclusions: Social costs can substantially modify the results of the economic evaluations. Therefore, taking into account social costs in diseases such as Alzheimer's can be a key element in making decisions about public financing and pricing of health interventions.