Defining the decision problem: A scoping review of economic evaluations for Clostridioides difficile interventions.

Structured Summary Background Clostridioides difficile infection (CDI) is the leading cause of health care-associated infectious diarrhoea. Several preventative and treatment interventions exist, however, decisions for their use are typically made independent of other interventions along the care pathway. Aim To assess how the scope of the decision problem is defined in economic evaluations of C. difficile interventions. Methods We conducted a scoping review following the Joanna Briggs Institute framework using a comprehensive literature search with C. difficile and economic evaluation as key search concepts. Study selection and extraction was performed independently by two reviewers. We conducted an in-depth analysis of all cost-utility and cost-effectiveness analyses. Care pathway domains (i.e., infection prevention and control, antimicrobial stewardship programs, prevention, diagnostics, treatment) were defined iteratively, and each study was classified according to the scope of the decision problem: a) one intervention, one domain; b) one intervention, multiple domains; c) multiple interventions, one domain; d) multiple interventions, multiple domains. Results A total of 3,886 studies were identified, 116 included in our descriptive overview, and 46 included in our in-depth analysis. Most studies limited the scope of the decision problem to one intervention (43/46; 93%). Only three studies (3/46; 7%) assessed multiple interventions – either as bundled versus standalone interventions for prevention (i.e., a single domain), or as sequences of treatments for initial and recurrent infection (i.e., multiple domains). No study assessed multiple interventions across prevention and treatment domains. Conclusions Economic evaluations for CDI assess narrowly defined decision problems which may have implications for optimal healthcare resource allocation.