Internal Medicine Post-Graduation Program, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2013 Apr 4;8(4):e59546. doi: 10.1371/journal.pone.0059546. Print 2013.
Latent tuberculosis infection (LTBI) is a reservoir for new TB cases. Isoniazid preventive therapy (IPT) reduces the risk of active TB by as much as 90%, but LTBI screening has limitations. Unlike tuberculin skin testing (TST), interferon-gamma release assays are not affected by BCG vaccination, and have been reported to be cost-effective in low-burden countries. The goal of this study was to perform a cost-effectiveness analysis from the health system perspective, comparing three strategies for LTBI diagnosis in TB contacts: tuberculin skin testing (TST), QuantiFERON®-TB Gold-in-Tube (QFT-GIT) and TST confirmed by QFT-GIT if positive (TST/QFT-GIT) in Brazil, a middle-income, high-burden country with universal BCG coverage.
METHODOLOGY/PRINCIPAL FINDINGS: Costs for LTBI diagnosis and treatment of a hypothetical cohort of 1,000 adult immunocompetent close contacts were considered. The effectiveness measure employed was the number of averted TB cases in two years. Health system costs were US$ 105,096 for TST, US$ 121,054 for QFT-GIT and US$ 101,948 for TST/QFT-GIT; these strategies averted 6.56, 6.63 and 4.59 TB cases, respectively. The most cost-effective strategy was TST (US$ 16,021/averted case). The incremental cost-effectiveness ratio was US$ 227,977/averted TB case for QFT-GIT. TST/QFT-GIT was dominated.
Unlike previous studies, TST was the most cost-effective strategy for averting new TB cases in the short term. QFT-GIT would be more cost-effective if its costs could be reduced to US$ 26.95, considering a TST specificity of 59% and US$ 18 considering a more realistic TST specificity of 80%. Nevertheless, with TST, 207.4 additional people per 1,000 will be prescribed IPT compared with QFT.
潜伏性结核感染（LTBI）是新结核病例的蓄水池。异烟肼预防治疗（IPT）可将活动性结核的风险降低多达 90%，但 LTBI 筛查存在局限性。与结核菌素皮肤试验（TST）不同，干扰素 -γ释放试验不受卡介苗接种的影响，并已报告在低负担国家具有成本效益。本研究的目的是从卫生系统的角度进行成本效益分析，比较三种 LTBI 诊断策略在结核接触者中的应用：结核菌素皮肤试验（TST）、QuantiFERON®-TB Gold-in-Tube（QFT-GIT）和 TST 阳性时 QFT-GIT 确认（TST/QFT-GIT），在巴西，这是一个中高收入、普遍覆盖卡介苗的高负担国家。
方法/主要发现：考虑了一个假设的 1000 名免疫功能正常的密切接触者的 LTBI 诊断和治疗的成本。采用的有效性衡量标准是两年内预防的结核病例数。卫生系统成本分别为 TST 105096 美元、QFT-GIT 121054 美元和 TST/QFT-GIT 101948 美元；这些策略分别预防了 6.56、6.63 和 4.59 例结核病例。最具成本效益的策略是 TST（每例预防病例 16021 美元）。增量成本效益比为 QFT-GIT 预防 1 例结核病例的成本效益比为 227977 美元。TST/QFT-GIT 处于劣势。
与之前的研究不同，TST 是短期内预防新结核病例最具成本效益的策略。如果 QFT-GIT 的成本能够降低到 26.95 美元，考虑到 TST 的特异性为 59%，或者更现实地考虑到 TST 的特异性为 80%，则 QFT-GIT 会更具成本效益。尽管如此，与 QFT 相比，每 1000 人将有 207.4 人被开具 IPT 处方。
