A cost-effectiveness study of tuberculosis and latent tuberculosis infection screening in prisons in Japan

Abstract

BACKGROUND: Prison inmates are considered a high-risk population for tuberculosis (TB) in Japan. However, they are currently only screened for active TB using chest X-ray (CXR) as part of an annual health check.OBJECTIVE: To evaluate the cost-effectiveness of screening for latent TB infection (LTBI) using interferon-gamma release assay (IGRA) on entry into prison institutions.METHOD: We developed a transmission model of TB, taking into consideration the TB and LTBI epidemiology among inmates in Japan. Using a decision tree, we compared and evaluated no screening, screening using CXR, and IGRA screening for LTBI with CXR upon entry for a hypothetical cohort of 10 000 persons, aged ≥20 years; active TB cases prevented was the health outcome.RESULTS: It was estimated that 314 active TB cases would occur in the absence of any screening policy. IGRA with CXR screening averted 176 cases, while just one case of active TB was averted with CXR only screening. The incremental cost-effectiveness ratio per active TB case prevented was respectively US$2672 and US$43 984 for IGRA + CXR screening and CXR only screening.CONCLUSION: Screening with IGRA should be considered as the most cost-effective screening policy for prison inmates.