Division of Infectious Diseases, Massachusetts General Hospital, Boston, 02114, USA.
AIDS. 2012 May 15;26(8):987-95. doi: 10.1097/QAD.0b013e3283522d47.
In settings with high tuberculosis (TB) prevalence, 15-30% of HIV-infected individuals initiating antiretroviral therapy (ART) have undiagnosed TB. Such patients are usually screened by symptoms and sputum smear, which have poor sensitivity.
To project the clinical and economic outcomes of using Xpert MTB/RIF(Xpert), a rapid TB/rifampicin-resistance diagnostic, to screen individuals initiating ART.
We used a microsimulation model to evaluate the clinical impact and cost-effectiveness of alternative TB screening modalities - in all patients or only symptomatic patients - for hypothetical cohorts of individuals initiating ART in South Africa (mean CD4 cell count = 171 cells/μl; TB prevalence 22%). We simulated no active screening and four diagnostic strategies, smear microscopy (sensitivity 23%); smear and culture (sensitivity, 100%); one Xpert sample (sensitivity in smear-negative TB: 43%); two Xpert samples (sensitivity in smear-negative TB: 62%). Outcomes included projected life expectancy, lifetime costs (2010 US$), and incremental cost-effectiveness ratios (ICERs). Strategies with ICERs less than $7100 (South African gross domestic product per capita) were considered very cost-effective.
Compared with no screening, life expectancy in TB-infected patients increased by 1.6 months using smear in symptomatic patients and by 6.6 months with two Xpert samples in all patients. At 22% TB prevalence, the ICER of smear for all patients was $2800 per year of life saved (YLS), and of Xpert (two samples) for all patients was $5100/YLS. Strategies involving one Xpert sample or symptom screening were less efficient.
Model-based analysis suggests that screening all individuals initiating ART in South Africa with two Xpert samples is very cost-effective.
在结核病（TB）高发地区，约有 15%-30%接受抗逆转录病毒治疗（ART）的 HIV 感染者存在未确诊的 TB。这些患者通常通过症状和痰涂片筛查，但其灵敏度较差。
评估使用 Xpert MTB/RIF（Xpert）——一种快速 TB/利福平耐药诊断检测——筛查开始接受 ART 的个体的临床和经济结局。
我们使用微观模拟模型来评估替代 TB 筛查方法的临床影响和成本效益——在所有患者或仅症状性患者中——对于在南非开始接受 ART 的假想队列。我们模拟了无主动筛查和四种诊断策略：涂片显微镜检查（灵敏度 23%）；涂片和培养（灵敏度 100%）；一个 Xpert 样本（在涂片阴性 TB 中的灵敏度：43%）；两个 Xpert 样本（在涂片阴性 TB 中的灵敏度：62%）。结果包括预期寿命、终生成本（2010 年美元）和增量成本效益比（ICER）。ICER 低于 7100 美元（南非人均国内生产总值）的策略被认为具有很高的成本效益。
与无筛查相比，在症状性患者中使用涂片筛查可使 TB 感染者的预期寿命延长 1.6 个月，在所有患者中使用两个 Xpert 样本可延长 6.6 个月。在 22%的 TB 流行率下，涂片用于所有患者的 ICER 为每年每挽救 1 个生命（YLS）2800 美元，而对于所有患者的 Xpert（两个样本）为 5100 美元/YLS。涉及一个 Xpert 样本或症状筛查的策略效率较低。
基于模型的分析表明，在南非对所有开始接受 ART 的个体进行两次 Xpert 样本筛查具有很高的成本效益。
