Clinical impact and cost analysis of the use of either the Xpert MTB Rif test or sputum smear microscopy in the diagnosis of pulmonary tuberculosis in Rio de Janeiro, Brazil.

INTRODUCTION: The molecular test Xpert MTB/RIF (Xpert) has been recommended for use in the diagnosis of pulmonary tuberculosis (PTB); however, data on the cost of incorporating it under routine conditions in high-burden countries are scarce. The clinical impact and costs incurred in adopting the Xpert test in routine PTB diagnosis was evaluated in a prospective study conducted from November 2012 to November of 2013, in the City of Rio de Janeiro, Brazil. METHODS: The diagnostic and therapeutic cascade for TB treatment was evaluated using Xpert in the first stage (S1), and sputum smear microscopy (SSM) in the second stage (S2). The mean costs associated with each diagnostic test were calculated including equipment, human resources, supplies, and infrastructure. RESULTS: We included 232 subjects with probable TB (S1 = 87; S2 = 145). The sensitivities of Xpert and SSM were 91.7% (22/24) and 79.1% (34/43), respectively. The median time between triage and TB treatment initiation in S1 (n = 24) was 14.5 days (IQR 8-28.0) and in S2 (n = 43) it was 8 days [interquartile range (IQR) 6-12.0]. The estimated mean costs per examination in S1 and S2 were US$24.61 and US$6.98, respectively. CONCLUSIONS: Compared with SSM, Xpert test showed a greater sensitivity, but it also had a time delay with respect to treatment initiation and a higher mean cost per examination.

Clinical impact and cost analysis of the use of either the Xpert MTB Rif test or sputum smear microscopy in the diagnosis of pulmonary tuberculosis in Rio de Janeiro, Brazil

Abstract INTRODUCTION: The molecular test Xpert MTB/RIF (Xpert) has been recommended for use in the diagnosis of pulmonary tuberculosis (PTB); however, data on the cost of incorporating it under routine conditions in high-burden countries are scarce. The clinical impact and costs incurred in adopting the Xpert test in routine PTB diagnosis was evaluated in a prospective study conducted from November 2012 to November of 2013, in the City of Rio de Janeiro, Brazil. METHODS: The diagnostic and therapeutic cascade for TB treatment was evaluated using Xpert in the first stage (S1), and sputum smear microscopy (SSM) in the second stage (S2). The mean costs associated with each diagnostic test were calculated including equipment, human resources, supplies, and infrastructure. RESULTS: We included 232 subjects with probable TB (S1 = 87; S2 = 145). The sensitivities of Xpert and SSM were 91.7% (22/24) and 79.1% (34/43), respectively. The median time between triage and TB treatment initiation in S1 (n = 24) was 14.5 days (IQR 8-28.0) and in S2 (n = 43) it was 8 days [interquartile range (IQR) 6-12.0]. The estimated mean costs per examination in S1 and S2 were US$24.61 and US$6.98, respectively. CONCLUSIONS: Compared with SSM, Xpert test showed a greater sensitivity, but it also had a time delay with respect to treatment initiation and a higher mean cost per examination.

Screening for active pulmonary tuberculosis: Development and applicability of artificial neural network models.

Tuberculosis (TB) remains a significant public health challenge, motivated by the diversity of healthcare epidemiological settings, as other factors. Cost-effective screening has substantial importance for TB control, demanding new diagnostic tools. This paper proposes a decision support tool (DST) for screening pulmonary TB (PTB) patients at a secondary clinic. The DST is composed of an adaptive resonance model (iART) for risk group identification (low, medium and high) and a multilayer perceptron (MLP) neural network for classifying patients as active or inactive PTB. Our tool attains an overall sensitivity (SE) and specificity (SP) of 92% (95% CI; 79-97) and 58% (95% CI; 47-68), respectively. SE values for smear-positive and smear-negative patients are 96% (95% CI; 80-99) and 82% (95% CI; 52-95), as well as higher than 83% (95% CI; 43-97) in low and high-risk cases. Even in scenarios with prevalence up to 20%, negative predictive values superior to 95% are obtained. The proposed DST provides a quick and low-cost pretest for presumptive PTB patients, which is useful to guide confirmatory testing and patient management, especially in settings with limited resources in low and middle-incoming countries.

Liquid vs Solid Culture Medium to Evaluate Proportion and Time to Change in Management of Suspects of Tuberculosis-A Pragmatic Randomized Trial in Secondary and Tertiary Health Care Units in Brazil.

BACKGROUND: The use of liquid medium (MGIT960) for tuberculosis (TB) diagnosis was recommended by WHO in 2007. However, there has been no evaluation of its effectiveness on clinically important outcomes. METHODS AND FINDINGS: A pragmatic trial was carried out in a tertiary hospital and a secondary health care unit in Rio de Janeiro City, Brazil. Participants were 16 years or older, suspected of having TB. They were excluded if only cerebral spinal fluid or blood specimens were available for analysis. MGIT960 technique was compared with the Lowenstein-Jensen (LJ) method for laboratory diagnosis of active TB. Primary outcome was the proportion of patients who had their initial medical management changed within 2 months after randomisation. Secondary outcomes were: mean time for changing the procedure, patient satisfaction with the overall treatment and adverse events. Data were analysed by intention-to-treat. Between April 2008 and September 2011, 693 patients were enrolled (348 to MGIT, 345 to LJ). Smear and culture results were positive for 10% and 15.7% of participants, respectively. Patients in the MGIT arm had their initial medical management changed more frequently than those in the LJ group (10.1% MGIT vs 3.8% LJ, RR 2.67 95% CI 1.44-.96, p = 0.002, NNT 16, 95% CI 10-39). Mean time for changing the initial procedure was greater in LJ group at both sites: 20.0 and 29.6 days in MGIT group and 52.2 and 64.3 in LJ group (MD 33.5, 95% CI 30.6-36.4, p = 0.0001). No other important differences were observed. CONCLUSIONS: This study suggests that opting for the MGIT960 system for TB diagnosis provides a promising case management model for improving the quality of care and control of TB. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN79888843.

Avaliação de um escore clínico para rastreamento de suspeitos de tuberculose pulmonar / Assessment of a clinical score for screening suspected pulmonary tuberculosis cases / Evaluación de un escore para rastreo de sospechosos de tuberculosis pulmonar

OBJETIVO: Avaliar acurácia de escore clínico (sensibilidade) no diagnóstico presuntivo de tuberculose pulmonar em triagem. MÉTODOS: Estudo descritivo-analítico transversal com 1.365 pacientes atendidos no setor de pneumologia em Unidade Básica de Saúde de nível secundário da cidade do Rio de Janeiro, RJ, de 2006 a 2007. Os participantes responderam um questionário padronizado, aplicado por equipe de enfermagem, contendo informações referentes à idade, peso e sintomas clínicos. O resultado presuntivo do diagnóstico de tuberculose pulmonar foi obtido pela soma da pontuação dos dados coletados. Diagnóstico de tuberculose ativa baseou-se nos resultados bacteriológicos e na decisão médica. Foram calculados sensibilidade, especificidade, valores preditivos positivos e negativos para uma prevalência especificada, e intervalos de 95 por cento de confiança para diversos pontos de corte do escore. O desempenho do escore foi avaliado pela curva receiver operating characteristic (ROC). RESULTADOS: Para o diagnóstico de tuberculose, tosse > 1 semana e > 3 semanas mostrou sensibilidade respectivamente de 88,2 por cento (86,2;90,2) e de 61,1 por cento (57,93;64,3), especificidade de 19,2 por cento (16,6;21,8) e 51,3 por cento (48,1;54,5). O escore clínico com 8 pontos mostrou uma sensibilidade de 83,13 por cento (77,8;87,6), especificidade de 51,8 por cento (48,5;55,1), valor preditivo positivo de 91,6 por cento (90,0;83,2) e negativo 32,9 por cento (30,1;35,7). CONCLUSÕES: Tosse (> 3 sem) apresentou baixa sensibilidade e especificidade. Escore clínico com elevada sensibilidade pode ser uma ferramenta alternativa na detecção de tuberculose pulmonar, pois, além de agilizar o atendimento do caso suspeito na unidade, permite padronizar a primeira abordagem pela enfermagem.

OBJECTIVE: To assess the accuracy (sensitivity) of a clinical score for presumptive pulmonary tuberculosis cases during screening. METHODS: Descriptive cross-sectional study comprising 1,365 patients attending the department of lung diseases at a secondary care outpatient clinic in the city of Rio de Janeiro, Southeastern Brazil, during 2006 and 2007. All respondents answered a standardized questionnaire administered by the clinic's nursing staff. Information on age, weight and clinical symptoms were collected. The presumptive diagnosis of pulmonary tuberculosis was made by summing up the scores of the data collected. The diagnosis of active tuberculosis was based on bacteriological findings and medical criteria. There were estimated sensitivity, specificity, positive predictive value and negative predictive value for a set prevalence, and 95 percent confidence intervals for different score cutoffs. The score performance was assessed using the receiver operating characteristic (ROC) curve. RESULTS: For the diagnosis of tuberculosis, cough for more than one week and cough for more than three weeks showed a sensitivity of 88.2 percent (86.2, 90.2) and 61.1 percent (57.93, 64.3), specificity 19.2 percent (16.6, 21.8) and 51.3 percent (48.1, 54.5), respectively. The clinical score of 8 had a sensitivity of 83.13 percent (77.8, 87.6), specificity of 51.8 percent (48.5, 55.1), positive predictive value of 91.6 percent (90.0, 83.2) and negative predictive value of 32.9 percent (30.1, 35.7). CONCLUSIONS: Cough for more than three weeks showed low sensitivity and specificity. A highly sensitive clinical score can be an alternative tool for screening pulmonary tuberculosis as it allows early care of suspected cases and standard nursing care approach.

OBJETIVO: Evaluar la exactitud de escore clínico (sensibilidad) en el diagnostico presuntivo de tuberculosis pulmonar en pesquisa. MÉTODOS: Estudio descriptivo-analítico transversal con 1.365 pacientes atendidos en el sector de pneumonologia en Unidad Básica de Salud de nivel secundario de la ciudad de Rio de Janeiro, Sureste de Brasil, de 2006 a 2007. Los participantes respondieron un cuestionario estandarizado, aplicado por equipo de enfermería, conteniendo informaciones referentes a la edad, peso y síntomas clínicos. El resultado presuntivo del diagnostico de tuberculosis pulmonar fue obtenido por la suma de puntuación de los datos colectados. Diagnostico de tuberculosis activa se basó en los resultados bacteriológicos y en la decisión medica. Se calcularon sensibilidad, especificidad, valores predictivos positivos negativos para una prevalencia especificada, e intervalos de 95 por ciento de confianza para diversos puntos de corte del escore. El desempeño del escore fue evaluado por la curva receiver operating characteristic (ROC). RESULTADOS: Para diagnostico de tuberculosis, tos > 1 semana y > 3 semanas mostró sensibilidad respectivamente de 88,2 por ciento (86,2;90,2) y de 61,1 por ciento (57,93;64,3), especificidad de 19,2 por ciento (16,6;21,8) y 51,3 por ciento (48,1;54,5). El escore clínico con 8 puntos mostró una sensibilidad de 83,13 por ciento(77,8;87,6), especificidad de 51,8 por ciento (48,5;55,1), valor predictivo positivo de 91,6 por ciento (90,0;83,2) negativo 32,9 por ciento (30,1;35,7). CONCLUSIONES: Tos (>3 sem) presentó baja sensibilidad y especificidad. Escore clínico con elevada sensibilidad puede ser una herramienta alternativa en la detección de tuberculosis pulmonar, pues además de agilizar la atención del caso sospechoso en la unidad, permite estandarizar el primer abordaje por la enfermera.

Assessment of a clinical score for screening suspected pulmonary tuberculosis cases.

OBJECTIVE: To assess the accuracy (sensitivity) of a clinical score for presumptive pulmonary tuberculosis cases during screening. METHODS: Descriptive cross-sectional study comprising 1,365 patients attending the department of lung diseases at a secondary care outpatient clinic in the city of Rio de Janeiro, Southeastern Brazil, during 2006 and 2007. All respondents answered a standardized questionnaire administered by the clinic's nursing staff. Information on age, weight and clinical symptoms were collected. The presumptive diagnosis of pulmonary tuberculosis was made by summing up the scores of the data collected. The diagnosis of active tuberculosis was based on bacteriological findings and medical criteria. There were estimated sensitivity, specificity, positive predictive value and negative predictive value for a set prevalence, and 95% confidence intervals for different score cutoffs. The score performance was assessed using the receiver operating characteristic (ROC) curve. RESULTS: For the diagnosis of tuberculosis, cough for more than one week and cough for more than three weeks showed a sensitivity of 88.2% (86.2, 90.2) and 61.1% (57.93, 64.3), specificity 19.2% (16.6, 21.8) and 51.3% (48.1, 54.5), respectively. The clinical score of 8 had a sensitivity of 83.13% (77.8, 87.6), specificity of 51.8% (48.5, 55.1), positive predictive value of 91.6% (90.0, 83.2) and negative predictive value of 32.9% (30.1, 35.7). CONCLUSIONS: Cough for more than three weeks showed low sensitivity and specificity. A highly sensitive clinical score can be an alternative tool for screening pulmonary tuberculosis as it allows early care of suspected cases and standard nursing care approach.