Bunkyo City Public Health Center, Bunkyo City, Tokyo, Japan.
Mol Diagn Ther. 2010 Aug 1;14(4):229-36. doi: 10.1007/BF03256378.
The prevalence of tuberculosis (TB) in the elderly is higher than that in the general population, and elderly populations are considered a high-risk group. Currently, annual TB screening of Bacille Calmette-Guérin (BCG)-vaccinated people aged over 65 years is performed by an annual chest x-ray examination (CXR) in Japan. Interferon-gamma release assays (QuantiFERON-TB Gold and QuantiFERON-TB Gold In-Tube [QFT]) are new alternatives to the tuberculin skin test to diagnose latent TB infection (LTBI) that have no cross-reactivity with the BCG vaccine. We evaluated the cost effectiveness of QFT versus CXR versus no screening in BCG-vaccinated elderly populations.
We constructed a Markov model to evaluate the cost effectiveness of QFT, CXR, and no screening. The target population was a hypothetical cohort of 1000 immunocompetent 65-year-olds, using a societal perspective and a lifetime horizon. All costs and clinical benefits were discounted at a fixed annual rate of 3%.
In the base-case analysis, a no-screening strategy resulted in the lowest cost ($US303.51; 14.6475 quality-adjusted life-years [QALYs]) compared with CXR ($US393.22; 14.6477 QALYs) and QFT ($US525.45; 14.6516 QALYs) [year 2008 values]. The sensitivity of QFT, as well as the prevalence of TB and LTBI, influenced the cost effectiveness; when the sensitivity of QFT was higher than 0.89, QFT became more cost effective than providing no screening. As the prevalence of LTBI and TB increased, the QFT strategy became progressively more cost effective.
Providing no routine TB screening is currently the most cost-effective strategy for BCG-vaccinated elderly populations in Japan. There appears to be little role for CXR in TB screening of elderly populations. These findings may be applicable to other countries with intermediate and high TB risks when choosing optimal TB screening of elderly populations.
老年人结核病（TB）的患病率高于一般人群，老年人被认为是高危人群。目前，日本对 65 岁以上的卡介苗（BCG）接种者进行年度 TB 筛查，方法是每年进行一次胸部 X 光检查（CXR）。干扰素 - γ释放试验（QuantiFERON-TB Gold 和 QuantiFERON-TB Gold In-Tube [QFT]）是一种新的替代结核菌素皮肤试验来诊断潜伏性 TB 感染（LTBI）的方法，与 BCG 疫苗无交叉反应。我们评估了 QFT 与 CXR 与不筛查在 BCG 接种老年人中的成本效益。
我们构建了一个马尔可夫模型来评估 QFT、CXR 和不筛查的成本效益。目标人群是一组 1000 名免疫功能正常的 65 岁老年人，采用社会视角和终生时间范围。所有成本和临床效益均以固定的年贴现率 3%贴现。
在基准分析中，与 CXR（$US393.22；14.6477 QALYs）和 QFT（$US525.45；14.6516 QALYs）相比，不筛查策略的成本最低（$US303.51；14.6475 QALYs）[2008 年值]。QFT 的灵敏度以及 TB 和 LTBI 的患病率影响了成本效益；当 QFT 的灵敏度高于 0.89 时，QFT 比不提供筛查更具成本效益。随着 LTBI 和 TB 患病率的增加，QFT 策略的成本效益逐渐提高。
目前，日本为 BCG 接种的老年人提供常规 TB 筛查是最具成本效益的策略。对于老年人的 TB 筛查，CXR 的作用似乎不大。当选择优化老年人的 TB 筛查时，这些发现可能适用于其他中高 TB 风险的国家。
