Assessing transferability in systematic reviews of health economic evaluations - a review of methodological guidance

Objective For assessing cost-effectiveness, Health Technology Assessment (HTA) organisations may use primary economic evaluations (P-HEs) or Systematic Reviews of Health Economic evaluations (SR-HEs). A prerequisite for meaningful results of SR-HEs is that the results from existing P-HEs are transferable to the decision context (e.g, HTA jurisdiction). A particularly pertinent issue is the high variability of costs and resource needs across jurisdictions. Our objective was to review the methods documents of HTA organisations and compare their recommendations on considering transferability in SR-HE. Methods We systematically hand searched the webpages of 158 HTA organisations for relevant methods documents from 8th January to 31st March 2019. Two independent reviewers performed searches and selected documents according to pre-defined criteria. One reviewer extracted data in standardised and piloted tables and a second reviewer checked them for accuracy. We synthesised data using tabulations and in a narrative way. Results We identified 155 potentially relevant documents from 63 HTA organisations. Of these, 7 were included in the synthesis. The included organisations have different aims when preparing a SR-HE (e.g. to determine the need for conducting their own P-HE). The recommendations vary regarding the underlying terminology (e.g. transferability/generalisability), the assessment approaches (e.g. structure), the assessment criteria and the integration in the review process. Conclusion Only few HTA organisations address the assessment of transferability in their methodological recommendations for SR-HEs. Transferability considerations are related to different purposes. The assessment concepts and criteria are heterogeneous. Developing standards to consider transferability in SR-HEs is desirable.