(017) Forging a Path for Transporting Real-World Evidence: Existing Applications & Proposed Practices

Background: Transportability methods represent a promising approach for assessing the relevance of external real-world evidence (RWE) and producing local estimates of clinical effectiveness and safety. However, there is limited guidance on appropriate study design and results reporting for RWE studies.

Objectives: To inform good practices surrounding transportability for RWE generation and to support adoption and acceptance of transportability methods in the RWE context.

Methods: We conducted a targeted literature review to identify studies that transported an effect estimate of the clinical effectiveness/safety of a biomedical exposure to a target real-world population of interest. Records were identified from PubMed-indexed articles published any time before July 25, 2023 (inclusive). Two reviewers screened abstracts/titles and reviewed the full text of candidate studies to identify the final set of articles. Data on the key study characteristics (e.g., year of publication, therapeutic area, etc.), analytic method used, estimate transported, stated assumptions, and associated terminology were abstracted from each article.

Results: Of 458 unique records identified, six were retained in the final review. Articles were published between May 2021 and March 2023, focused on the North American context, and covered a range of therapeutic areas. Five of the articles (83.3%) used weighting methods to transport estimates; however, we noted differing terminology and descriptions for their approaches (despite applying equivalent methods). The remaining article used an outcome regression approach. Two studies discussed all transportability assumptions, and one evaluated the likelihood of meeting all assumptions and the impact of potential violations. Overall, the stable unit treatment value assumption for selection was the least discussed and evaluated across the identified case studies. Nonetheless, study authors mentioned and assessed other potential threats to validity (e.g., missingness and measurement error). In response to these findings, we developed a proposed template to aid in the evaluation and presentation of RWE transportability studies.

Conclusions: Our review suggested that the use of transportability methods for RWE generation is an emerging area of research and also highlighted some areas for improvement (e.g., harmonized terminology and more transparent methods/assumptions reporting) to increase the acceptability of these methods for producing robust evidence on treatment effectiveness and safety.