Diel Roland, Nienhaus Albert, Loddenkemper Robert
School of Public Health, c/o Institute for Medical Sociology, Heinrich Heine University, Post Box 101007, D-40001 Düsseldorf, Germany.
Chest. 2007 May;131(5):1424-34. doi: 10.1378/chest.06-2728.
To assess the cost-effectiveness of the new QuantiFERON-TB Gold In-Tube (QFT-G) [Cellestis; Carnegie, VIC, Australia] assay for screening and treating of persons who have had close contact with tuberculosis (TB) patients and are suspected of having latent tuberculosis infection (LTBI) [hereafter called close-contacts] in Germany.
The health and economic outcomes of isoniazid treatment of 20-year-old close-contacts were compared in a Markov model over a period of 20 years, using two different cutoff values for the tuberculin skin test (TST), the QFT-G assay alone, or the QFT-G assay as a confirmatory test for the TST results.
QFT-G assay-based treatment led to cost savings of $542.9 and 3.8 life-days gained per LTBI case. TST-based treatment at a 10-mm induration size cutoff gained $177.4 and 2.0 life-days gained per test-positive contact. When the cutoff induration size for the TST was reduced to 5 mm, the incremental cost-effectiveness ratio fell below the willingness-to-pay threshold ($30,170 per life-years gained) but resulted in unnecessary treatment of 77% of contacts owing to false-positive TST results. Combination with the 5-mm induration size TST cutoff value compared to the results of the QFT-G assay alone reduced the total costs per 1,000 contacts by 1.8% to $222,869. The number treated to prevent 1 TB case was 22 for the two QFT-G assay-based procedures, 40 for the TST at a cutoff induration size of 10 mm, and 96 for the TST at a cutoff induration size of 5 mm. When the sensitivity rates of the TST and the QFT-G assay were compounded, the QFT-G assay strategy alone was slightly less costly (0.6%) than the two-step approach.
Using the QFT-G assay, but especially combining the QFT-G assay following the TST screening of close-contacts at a cutoff induration size of 5 mm before LTBI treatment is highly cost-effective in reducing the disease burden of TB.
评估新型全血γ-干扰素释放试验（QFT-G）[Cellestis公司；澳大利亚维多利亚州卡内基]检测法在德国对曾与结核病（TB）患者密切接触且疑似潜伏性结核感染（LTBI）者（以下简称密切接触者）进行筛查和治疗的成本效益。
在一个马尔可夫模型中，对20岁密切接触者进行为期20年的异烟肼治疗的健康和经济结果进行比较，采用结核菌素皮肤试验（TST）的两种不同临界值、单独使用QFT-G检测法，或QFT-G检测法作为TST结果的确认试验。
基于QFT-G检测法的治疗每例LTBI病例可节省成本542.9美元，并增加3.8个生命天数。以硬结大小10毫米为临界值的基于TST的治疗，每例检测呈阳性的接触者可节省成本177.4美元，并增加2.0个生命天数。当TST的硬结临界大小降至5毫米时，增量成本效益比低于支付意愿阈值（每获得一个生命年30170美元），但由于TST结果出现假阳性，导致77%的接触者接受了不必要的治疗。与仅采用QFT-G检测法的结果相比，结合硬结大小5毫米的TST临界值可使每1000名接触者的总成本降低1.8%，降至222869美元。两种基于QFT-G检测法的程序预防1例结核病病例所需治疗的人数为22人，硬结临界大小为10毫米的TST为40人，硬结临界大小为5毫米的TST为96人。当将TST和QFT-G检测法的敏感度进行综合时，仅采用QFT-G检测法的策略成本略低（0.6%）于两步法。
使用QFT-G检测法，尤其是在对密切接触者进行LTBI治疗前，先以硬结大小为临界值进行5毫米的TST筛查后再结合QFT-G检测法，在减轻结核病疾病负担方面具有很高的成本效益。
