OBJECTIVES

: Tuberculosis (TB) in older people remains one of public health challenges in Hong Kong. In the absence of active response, current passive case-finding strategy has limited impact on TB elimination. In order to bridge research gap and inform local TB program, this study was conducted to examine the cost-effectiveness of screening strategies in older people on entry to long-term care facilities compared with current strategy.

METHODS

: From a health service provider perspective and 20-year time horizon, we structured a decision analysis and Markov model to compare four strategies: (i) current strategy, (ii) CXR screening and (iii) Xpert screening respectively represent TB screening in suspects by chest X-ray and Xpert MTB/RIF, and (iv) LTBI/TB screening represents screening for latent and active TB infection by Interferon-Gamma Release Assays and chest X-ray. The outcomes were direct medical costs, life-years, and quality-adjusted life-years (QALYs) measured by incremental cost-effectiveness ratio (ICER).

RESULTS

: In the base-case analysis, current strategy was the most cost-saving; CXR screening was dominated by Xpert screening; LTBI/TB screening gained the highest life-years and QALYs. The ICERs of LTBI/TB screening were US$19,712 and US$29,951 per QALY gained compared with non-dominated strategies. At the willingness-to-pay threshold of US$50,000 per QALY gained, LTBI/TB screening was the most cost-effective, particularly when probability of annual LTBI reactivation was greater than 0.155% and its screening acceptability was greater than 38% in one-way sensitivity analysis. In 1,000 iterations of Monte Carlo simulation, the probabilities of current strategy, CXR screening, Xpert screening, and LTBI/TB screening to be cost-effective were 0, 1.3%, 20.1%, and 78.6%, respectively.

CONCLUSIONS

: Screening for latent and active TB infection in high-risk older people appears highly effective and cost-effective. The key findings may provide an alternative solution to bring down TB endemic and warrant further research in areas like Hong Kong.