OBJECTIVES: Productivity losses and informal care are the main societal cost drivers in Cost-effectiveness analyses (CEA). Their inclusion, measurement and valuation might change the result of CEA, especially for health technology dedicated to disease associated with important spillover effects. The objective of this study was twofold: 1/updating current knowledge on methods used to measure and value societal costs in CEA, in the main pathologies of the systematic literature review and 2/identifying, for these pathologies, the impact on ICER of adopting a societal perspective versus non-societal perspective.

METHODS: We performed an international systematic literature review, using the methodological framework outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A search in the MEDLINE database using PubMed was performed, covering the period from 1st January 2013 to 1st January 2023.

RESULTS: 69 studies (among which 22 CEA) met the inclusion criteria and were included in the review. Amongst the CEA, main pathologies were neurodegenerative diseases (23%), mental diseases (18%) and cancer (14%). For these pathologies, informal care was always included. 92% of these twelve studies defined a measurement method for informal care (mainly CSRI). 75% of them described a valuation method: opportunity cost (44%) and replacement cost (55%). 58% of these twelve studies included productivity losses. 89% of them described a measurement method (mainly CSRI) and 88 % described a valuation method: human capital (67%) and friction costs (33%). Informal care was the societal cost having the greatest impact on the ICER. Compared to health care system perspective, adopting the societal perspective decreased the ICER in all concerned studies.

CONCLUSIONS: Informal care and productivity losses are the most described societal costs. In the papers comparing the ICER between CEA adopting societal perspective versus not, societal costs always positively affect the probability of the intervention being cost-effective, irrespective of the therapeutic area.