Modelling the Cost-Effectiveness of Latent Tuberculosis Screening and Treatment Strategies in Recent Migrants to a Low Incidence Setting.

Abstract

Many tuberculosis (TB) cases in low-incidence settings are attributed to reactivation of latent TB infection (LTBI) acquired overseas. We assessed the cost-effectiveness of community-based LTBI screening and treatment strategies in recent migrants to a low-incidence setting (Australia). A decision-analytic Markov model was developed that cycled one migrant cohort (≥11-year-olds) annually over a lifetime from 2020. Post-migration/onshore and offshore (screening during visa-application) strategies were compared to existing policy (chest-x-ray during visa application). Outcomes included TB cases averted and discounted cost per quality-adjusted life-year (QALY) gained from a health-sector perspective. Most recent migrants are young adults and cost-effectiveness is limited by their relatively low LTBI prevalence, low TB mortality risks and high emigration probability. Onshore strategies cost ≥A$203,188 per QALY gained, preventing ~2.3-7.0% of TB cases in the cohort. Offshore strategies (screening costs incurred by migrants) cost ≥A$13,907 per QALY gained, preventing 5.5-16.9%. Findings were most sensitive to the LTBI treatment quality-of-life decrement (further to severe-adverse-events); with a minimal decrement, all strategies caused more ill-health than they prevented. Additional LTBI strategies in recent migrants could only marginally contribute to TB elimination and are unlikely to be cost-effective unless screening costs are borne by migrants and potential LTBI treatment quality-of-life decrements are ignored.