Introduction: In light of the lack of an agreed international standard for how to conduct cost-effectiveness analyses (CEAs), including cost-utility analyses (CUAs) from a societal perspective, there is uncertainty regarding to what extent the inclusion of productivity losses/gains in economic evaluations can affect cost-effectiveness results and subsequently decisions on whether to recommend new health technologies. To investigate this, we conducted a systematic review of CEAs and CUAs of drug-based therapies for a set of chronic immune-mediated disorders to understand how cost elements and calculation methods related to productivity losses/gains are used, examine the impact on the incremental cost-effectiveness ratio (ICER) of including productivity costs, and explore factors that affect the inclusion of productivity loss.
Methods: Databases (MEDLINE® In-process, MEDLINE, Embase and Cochrane Library) were searched from January 2010 to October 2020 by two independent reviewers for all CEAs and CUAs in adults with any of the following conditions: ankylosing spondylitis, chronic idiopathic urticaria, Crohn's disease, fibromyalgia, juvenile idiopathic arthritis, psoriasis, rheumatoid arthritis, systemic lupus erythematosus and ulcerative colitis. Relevant study data were extracted and evidence was synthesized for both qualitative and quantitative analysis. Productivity cost elements including absenteeism, presenteeism, unemployment/early retirement, premature mortality and informal care were extracted, along with the method used to determine them. A multivariate analysis was performed to identify factors associated with the inclusion of productivity loss.
Results: Our searches identified 5016 records, culminating in 198 unique studies from 234 publications following screening. Most of the studies investigated rheumatoid arthritis (37.0%) or psoriasis (32.0%). The majority were CUAs, with some including both a CEA and a CUA (73.0%). Most studies used a payer perspective only (28.5%) or a societal perspective only (21.0%). Of the 49 studies incorporating productivity losses/gains, 42 reported the type of cost element used; all of these used patient absenteeism, either alone or in addition with other elements. Only 16 studies reported the method used to value productivity changes, of which eight used a human capital approach, four used a friction cost approach and four used both approaches. Twenty-eight of the 49 studies (57.1%) reported inclusion of productivity losses/gains as contributing to more favourable cost-effectiveness outcomes and ICERs, while 12 (24.5%) reported no substantial impact. On the basis of a multivariate analysis, rheumatoid arthritis as the target disease had a statistically significant association with the inclusion of productivity loss compared with psoriasis and inflammatory bowel disease.
Conclusions: The results of our review suggest that incorporating productivity cost elements may positively affect cost-effectiveness outcomes in evaluations of therapeutics for immune-mediated disorders. Our work highlights the continued need for clarity when reporting how CEAs and CUAs in this disease area are conducted, in order to better inform healthcare decision-making.
Keywords: Cost-effectiveness analysis; Cost-utility analysis; Health technology assessment; Indirect cost; Productivity loss; Psoriasis; Rheumatoid arthritis; Systematic literature review.
© 2022. The Author(s).