OBJECTIVES: There are differences regarding to what extent the inclusion of productivity losses/gains in cost-effectiveness analyses (CEAs), including cost-utility analyses (CUAs). We conducted a systematic review of CEAs and CUAs of drugs for chronic immune-mediated disorders to understand how cost elements and cost calculation methods related to productivity losses/gains are used and examine the impact of including productivity costs on economic outcomes.

METHODS: MEDLINE, Embase, and Cochrane Library were searched from January 2010 to October 2020 for all CEAs and CUAs in adults including 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. Productivity cost elements including absenteeism, presenteeism, unemployment/early retirement, premature mortality, and informal care were extracted, along with the method used to determine them.

RESULTS: Our searches identified 5,021 records, identified 200 unique studies from 234 publications following screening. Most of the studies investigated rheumatoid arthritis (37.0%) or psoriasis (32.0%). The majority were CUAs (73.0%), with some including both a CEA and a CUA. 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. 28 of the 49 studies (57.1%) reported inclusion of productivity losses/gains as contributing to more favourable cost-effectiveness, while 12 (24.5%) reported no significant impact. 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.

CONCLUSIONS: This study suggests that incorporating productivity cost elements may positively affect cost-effectiveness outcomes in evaluations for chronic immune-mediated disorders. Our work highlights the continued need for clarity when reporting how CEAs and CUAs in this disease area are conducted.