Methods Used in Economic Evaluations of Tuberculin Skin Tests and Interferon Gamma Release Assays for the Screening of Latent Tuberculosis Infection: A Systematic Review

Abstract

Background: Latent tuberculosis infection (LTBI) provides a constant pool of new active tuberculosis cases; a third of the earth's population is estimated to be infected with LTBI.

Objective: The objective of this systematic review was to assess the quality and summarize the available evidence from published economic evaluations reporting on the cost-effectiveness of tuberculin skin tests (TSTs) compared with interferon gamma release assays (IGRAs) for the screening of LTBI.

Methods: An extensive systematic review of the published literature was conducted. A two-step process was adopted to identify relevant articles: information was extracted into evidence tables and then analyzed. The quality of the publications was assessed using a 10-item checklist specific for economic evaluations.

Results: Twenty-eight studies were identified for inclusion in this review. Most of the studies found IGRAs to be more cost-effective than TSTs; however, the conclusions from the studies varied significantly. Most studies scored highly on the checklist although only one fulfilled all the stipulated criteria. A wide variety of methodological approaches were documented; identified differences included the type of economic evaluation and model, time horizon, perspective, and outcomes measures.

Conclusions: The lack of consistent methods across studies makes it difficult to draw any firm conclusions about the most cost-effective option between TSTs and IGRAs. This problem can be solved by improving the quality of economic evaluation studies in the field of LTBI screening, through adherence to quality checklists.

Keywords: economic evaluations; interferon gamma release assays; screening; systematic review; tuberculin skin tests; tuberculosis.