Variation in Model-Based Economic Evaluations of Low Dose Computed Tomography (LDCT) Screening for Lung Cancer: a Methodological Review

Abstract

Objectives: There is significant heterogeneity in the results of published model-based economic evaluations of low dose computed tomography (LDCT) screening for lung cancer. We sought to understand and demonstrate how these models differ. Methods: An expansion and update of a previous systematic review (n=19). Databases (including Medline and Embase) were searched. Studies were included if strategies involving (single or multiple) LDCT screening were compared to no screening or other imaging modalities, in a population at risk of lung cancer. More detailed data extraction of studies from the previous review was conducted. Studies were critically appraised using the Consensus Health Economic Criteria list. Results: Sixteen new studies met the inclusion criteria, giving a total of 35 studies. There are geographic and temporal differences, and differences in screening intervals and eligible populations. Studies varied in the types of models used, e.g. decision tree, Markov, microsimulation models. Most conducted a cost-effectiveness analyses (using life years gained) or cost-utility analysis. The potential for overdiagnosis was considered in many models, unlike with other potential consequences of screening. Some studies report considering lead-time bias, but fewer mention length bias. Generally, the more recent studies, involving more complex modelling, tended to meet more of the critical appraisal criteria, with notable exceptions. Conclusions: There are many differences across the economic evaluations contributing to variation in estimates of the cost-effectiveness of LDCT screening for lung cancer. A number of methodological factors and evidence needs have been highlighted that will require consideration in future economic evaluations to achieve better agreement.