Purpose: Tuberculosis (TB) is a long-standing and expanding threat to global public health. Recognizing and treating latent tuberculosis (defined as infection without active disease) is an important step for long-standing control. Recently, a new diagnostic strategy for latent TB, interferon-gamma release assays, as exemplified by Quantiferon, has become available. This new diagnostic modality is more specific, particularly in endemic areas where BCG-vaccination rates are high. The purpose of this study is to evaluate the cost-effectiveness of screening with the standard tuberculin skin test and QuantiFERON for latent tuberculosis in children of endemic countries.
Method: A computer-based Markov model was developed that consisted of ten disease states. The probabilities of transition and associated costs and utilities of each disease state were obtained by a systematic review of the literature. The cost-effectiveness of universal screening and treatment for latent TB in children at age two or at age two and five was evaluated. The model was run in 1 month cycle lengths until everyone died to account for future costs and utilities.
Results: The results of our analysis show that both one-time screening with QuantiFERON at age 2 and repeat screening with QuantiFERON at age 2 and age 5 have incremental cost-effective ratios over no screening that are highly cost effective. One time screening with the tuberculin skin test is strictly dominated (i.e. less effective and more costly) by both QuantiFERON screening options while repeat TST screening is strictly dominated by repeat QuantiFERON screening. The variables to which this analysis is most sensitive are the rate of getting latent TB in an endemic area and the prevalence of latent TB in children in an endemic area.
Conclusion: In summary, further exploration into the true prevalence of latent TB in endemic areas, annual risk of becoming infected, and a better understanding of screening test characteristics would be useful areas of research. Until these are performed, our analysis suggests that screening and treating children for latent TB in an endemic area is a cost-effective measure to combat the global burden of TB.
Candidate for the Lee B. Lusted Student Prize Competition