基因测试作为最经济手段防控监狱中的结核病

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导读

在11月27日的《公共图书馆•医学》网络版上，斯坦福大学的研究人员和他们的合作者描述了一个DNA测序设备GeneXpert。和WHO目前推荐的方法相比，GeneXpert在监狱环境中是最划算的诊断和预防结核病扩散的方法。

斯坦福大学的研究人员表示，DNA测序是最划算的筛选监狱中耐药菌株的方法。

在治疗和预防结核病的过程中，诊断可能是最弱的一环。结核病是一种传染病。根据世界卫生组织（WHO）的数据，结核杆菌每年会感染900万人，并导致150万人死亡。在11月27日的《公共图书馆•医学》（PLoS Medicine）网络版上，斯坦福大学的研究人员和他们的合作者描述了一个DNA测序设备GeneXpert。和WHO目前推荐的方法相比，GeneXpert在监狱环境中是最划算的诊断和预防结核病扩散的方法。


前苏联的监狱是世界上结核病感染率最高的地方之一。监狱的囚犯患病概率是一般人群的10倍，而且非常容易患有抗药性的结核病。他们导致的问题还不仅限于自身，因为当被释放以后，这些囚犯还会把病菌传播给跟他们接触的人。囚犯扮演了疾病保留地的角色。虽然胸透X光可以诊断结核，但是却不能区分需用常规药物的菌株和产生了抗药性的菌株，后者需要更贵的药物。GeneXpert可以从一小块结缔组织样本中迅速诊断出菌株类型。


不过，这一遗传筛选测试比其他诊断方法更昂贵。所以斯坦福大学的研究人员开始决定在治疗早期就使用高价检测从长期来看是否合算。利用计算机模型，研究人员预测GeneXpert能在4年内把服刑人员的结核感染率下降20%，前提是他们需要恰当的药物治疗。根据这项研究的新闻稿，研究作者表示这些研究可以帮助政府和医学界制定对抗结核病的决策。


看起来这种方法很有吸引力：WHO在2010年底赞同使用遗传分析技术，并正密切关注着这种技术在全球范围内越来越广泛的使用。

Screening and Rapid Molecular Diagnosis of Tuberculosis in Prisons in Russia and Eastern Europe: A Cost-Effectiveness Analysis

Daniel E. Winetsky, Diana M. Negoescu, Emilia H. DeMarchis, Olga Almukhamedova, Aizhan Dooronbekova, Dilshod Pulatov, Natalia Vezhnina, Douglas K. Owens,, Jeremy D. Goldhaber-Fiebert

Background: Prisons of the former Soviet Union (FSU) have high rates of multidrug-resistant tuberculosis (MDR-TB) and are thought to drive general population tuberculosis (TB) epidemics. Effective prison case detection, though employing more expensive technologies, may reduce long-term treatment costs and slow MDR-TB transmission.

Methods and Findings: We developed a dynamic transmission model of TB and drug resistance matched to the epidemiology and costs in FSU prisons. We evaluated eight strategies for TB screening and diagnosis involving, alone or in combination, self-referral, symptom screening, mass miniature radiography (MMR), and sputum PCR with probes for rifampin resistance (Xpert MTB/RIF). Over a 10-y horizon, we projected costs, quality-adjusted life years (QALYs), and TB and MDR-TB prevalence. Using sputum PCR as an annual primary screening tool among the general prison population most effectively reduced overall TB prevalence (from 2.78% to 2.31%) and MDR-TB prevalence (from 0.74% to 0.63%), and cost US$543/QALY for additional QALYs gained compared to MMR screening with sputum PCR reserved for rapid detection of MDR-TB. Adding sputum PCR to the currently used strategy of annual MMR screening was cost-saving over 10 y compared to MMR screening alone, but produced only a modest reduction in MDR-TB prevalence (from 0.74% to 0.69%) and had minimal effect on overall TB prevalence (from 2.78% to 2.74%). Strategies based on symptom screening alone were less effective and more expensive than MMR-based strategies. Study limitations included scarce primary TB time-series data in FSU prisons and uncertainties regarding screening test characteristics.

Conclusions: In prisons of the FSU, annual screening of the general inmate population with sputum PCR most effectively reduces TB and MDR-TB prevalence, doing so cost-effectively. If this approach is not feasible, the current strategy of annual MMR is both more effective and less expensive than strategies using self-referral or symptom screening alone, and the addition of sputum PCR for rapid MDR-TB detection may be cost-saving over time.