Schmid Karen Barros, Scherer Luciene, Barcellos Regina Bones, Kuhleis Daniele, Prestes Isaías Valente, Steffen Ricardo Ewbank, Dalla Costa Elis Regina, Rossetti Maria Lucia Rosa
Centro de Desenvolvimento Científico e Tecnológico (CDCT), Fundação Estadual de Produção e Pesquisa em Saúde (FEPPS), Av. Ipiranga 5400, 3° andar, CEP 90610-000, Porto Alegre, Rio Grande do Sul, Brazil.
Universidade Luterana do Brasil (ULBRA), Canoas, Brazil.
BMC Infect Dis. 2014 Dec 16;14:678. doi: 10.1186/s12879-014-0678-x.
Prison conditions can favor the spread of tuberculosis (TB). This study aimed to evaluate in a Brazilian prison: the performance and accuracy of smear, culture and Detect-TB; performance of smear plus culture and smear plus Detect-TB, according to different TB prevalence rates; and the cost-effectiveness of these procedures for pulmonary tuberculosis (PTB) diagnosis.
This paper describes a cost-effectiveness study. A decision analytic model was developed to estimate the costs and cost-effectiveness of five routine diagnostic procedures for diagnosis of PTB using sputum specimens: a) Smear alone, b) Culture alone, c) Detect-TB alone, d) Smear plus culture and e) Smear plus Detect-TB. The cost-effectiveness ratio of costs were evaluated per correctly diagnosed TB case and all procedures costs were attributed based on the procedure costs adopted by the Brazilian Public Health System.
A total of 294 spontaneous sputum specimens from patients suspected of having TB were analyzed. The sensibility and specificity were calculated to be 47% and 100% for smear; 93% and 100%, for culture; 74% and 95%, for Detect-TB; 96% and 100%, for smear plus culture; and 86% and 95%, for smear plus Detect-TB. The negative and positive predictive values for smear plus Detect-TB, according to different TB prevalence rates, ranged from 83 to 99% and 48 to 96%, respectively. In a cost-effectiveness analysis, smear was both less costly and less effective than the other strategies. Culture and smear plus culture were more effective but more costly than the other strategies. Smear plus Detect-TB was the most cost-effective method.
The Detect-TB evinced to be sensitive and effective for the PTB diagnosis when applied with smear microscopy. Diagnostic methods should be improved to increase TB case detection. To support rational decisions about the implementation of such techniques, cost-effectiveness studies are essential, including in prisons, which are known for health care assessment problems.
监狱环境可能有利于结核病（TB）的传播。本研究旨在评估巴西一所监狱中：涂片、培养和Detect-TB检测的性能及准确性；根据不同的结核病患病率，涂片加培养和涂片加Detect-TB检测的性能；以及这些程序在肺结核（PTB）诊断中的成本效益。
本文描述了一项成本效益研究。开发了一个决策分析模型，以估计使用痰标本诊断PTB的五种常规诊断程序的成本和成本效益：a）单独涂片，b）单独培养，c）单独使用Detect-TB检测，d）涂片加培养，e）涂片加Detect-TB检测。根据正确诊断的每例结核病病例评估成本效益比，所有程序成本均根据巴西公共卫生系统采用的程序成本进行计算。
共分析了294份疑似结核病患者的自发痰标本。计算得出涂片的敏感性和特异性分别为47%和100%；培养的敏感性和特异性分别为93%和100%；Detect-TB检测的敏感性和特异性分别为74%和95%；涂片加培养的敏感性和特异性分别为96%和100%；涂片加Detect-TB检测的敏感性和特异性分别为86%和95%。根据不同的结核病患病率，涂片加Detect-TB检测的阴性和阳性预测值分别为83%至99%和48%至96%。在成本效益分析中，涂片比其他策略成本更低且效果更差。培养和涂片加培养比其他策略更有效但成本更高。涂片加Detect-TB检测是最具成本效益的方法。
当与涂片显微镜检查一起应用时，Detect-TB检测在PTB诊断中表现出敏感性和有效性。应改进诊断方法以增加结核病病例的发现。为支持关于实施此类技术的合理决策，成本效益研究至关重要，包括在存在医疗保健评估问题的监狱中。
