A Scoping Review of Methods for Extrapolating Costs and Effects in Economic Evaluations of Remote Monitoring

Telehealth, including remote monitoring, has the potential to reduce healthcare resource use. However, economic evaluations often have insufficient methodological quality, including long-term investigation. The problem is that data are often unavailable for the entire time horizon of interest, but here different extrapolation methods can be applied.

The objective of this study is to examine how long-term economic evaluations of telehealth interventions (remote monitoring) have been designed and conducted with a particular focus on extrapolation methods, and to identify the applied extrapolation methods.

This scoping review was conducted according to guidelines in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR). The systematic search in Embase, PubMed, EconLit, Web of Science, NHS Economic Evaluation Database, and CINAHL, supplemented with a grey literature search in Google Scholar, identified economic evaluations, where minimum one alternative was telehealth, the time horizon exceeded 12 months, and extrapolation methods were applied. Last search date was 23 January 2025, and two reviewers screened the studies simultaneously. Data were extracted using a predefined data extraction sheet.

A total of 57 studies were included in this scoping review. Use of simpler extrapolation methods (Profiles and Constant values) was prevalent in 84% and 57% of the studies, respectively. These simple methods were used both in combination and alone. Even when trial-based data were available for a shorter time horizon, the simpler methods were used just as frequently as the more advanced methods. Only 32% of the studies included a sensitivity analysis for investigating the impact of the time horizon on the decision. Furthermore, transparency was missing in the reporting of applied extrapolation methods, and explicit investigation of uncertainty from the choice of extrapolation method is warranted.

This scoping review finds that economic evaluations of telehealth interventions (remote monitoring) mainly rely on simpler extrapolation methods with limited justification, validation, and uncertainty analysis. Further investigation into the implications of use of different extrapolation methods is warranted, and guidelines on use of extrapolation methods are needed to ensure transparency.

A protocol was published elsewhere.