Tuberculosis screening for long-term care: a cost-effectiveness analysis

SETTING: Long-term care facilities in Canada, a low tuberculosis (TB) incidence country. OBJECTIVE: To compare the impact and cost-effectiveness of three screening strategies for TB on entry to long-term care: no screening, screening for latent tuberculous infection (LTBI) using the tuberculin skin test (TST) or screening for active disease with a chest X-ray. DESIGN: Cost effectiveness analysis. RESULTS: With the LTBI screening strategy, the number needed to screen to prevent one active case was 1410 and the cost per case averted was Canadian $109913. The number needed to screen to prevent one case using the active screening strategy was 1266, and the cost per case averted was $672298. CONCLUSIONS: Our findings suggest that TB screening strategies on entry to long-term care are costly, with large numbers needed to screen. Screening with TST was more cost-effective than chest X-ray screening. Higher risk of reactivation of LTBI is associated with improved cost-effectiveness of screening. Short time horizons and test performance characteristics place limitations on screening programmes in this setting. Future considerations include the changing demographics of the institutionalised elderly.