9 research outputs found

    The ethics of testing a test: randomized trials of the health impact of diagnostic tests for infectious diseases.

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    In the last decade, many new rapid diagnostic tests for infectious diseases have been developed. In general, these new tests are developed with the intent to optimize feasibility and population health, not accuracy alone. However, unlike drugs or vaccines, diagnostic tests are evaluated and licensed on the basis of accuracy, not health impact (eg, reduced morbidity or mortality). Thus, these tests are sometimes recommended or scaled up for purposes of improving population health without randomized evidence that they do so. We highlight the importance of randomized trials to evaluate the health impact of novel diagnostics and note that such trials raise distinctive ethical challenges of equipoise, equity, and informed consent. We discuss the distinction between equipoise for patient-important outcomes versus diagnostic accuracy, the equity implications of evaluating health impact of diagnostics under routine conditions, and the importance of offering reasonable choices for informed consent in diagnostic trials

    Gender-related barriers and delays in accessing tuberculosis diagnostic and treatment services: a systematic review of qualitative studies. Tuberc Res Treat.

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    Background. Tuberculosis (TB) remains a significant global public health problem with known gender-related (male versus female) disparities. We reviewed the qualitative evidence (written/spoken narrative) for gender-related differences limiting TB service access from symptom onset to treatment initiation. Methods. Following a systematic process, we searched 12 electronic databases, included qualitative studies that assessed gender differences in accessing TB diagnostic and treatment services, abstracted data, and assessed study validity. Using a modified "inductive coding" system, we synthesized emergent themes within defined barriers and delays limiting access at the individual and provider/system levels and examined gender-related differences. Results. Among 13,448 studies, 28 studies were included. All were conducted in developing countries and assessed individual-level barriers; 11 (39%) assessed provider/system-level barriers, 18 (64%) surveyed persons with suspected or diagnosed TB, and 7 (25%) exclusively surveyed randomly sampled community members or health care workers. Each barrier affected both genders but had gendervariable nature and impact reflecting sociodemographic themes. Women experienced financial and physical dependence, lower general literacy, and household stigma, whereas men faced work-related financial and physical barriers and community-based stigma. Conclusions. In developing countries, barriers limiting access to TB care have context-specific gender-related differences that can inform integrated interventions to optimize TB services

    Field Evaluation of a Rapid Immunochromatographic Test for Tuberculosis

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    Rapid diagnostic tests for tuberculosis (TB) are needed to facilitate early treatment of TB and prevention of Mycobacterium tuberculosis transmission. The ICT Tuberculosis test is a rapid, card-based immunochromatographic test for detection of antibodies directed against M. tuberculosis antigens. The objective of the study was to evaluate the performance of the ICT Tuberculosis test for the diagnosis of active pulmonary TB (PTB) with whole blood, plasma, and serum from patients suspected of having PTB and from asymptomatic controls in a setting with a high prevalence of PTB. Seventy patients suspected of having PTB (and who were later confirmed to have or not to have PTB by use of M. tuberculosis culture as the “gold standard”) and 42 controls were studied. Twenty-one controls were neither vaccinated with Mycobacterium bovis bacillus Calmette-Guérin (BCG) nor tuberculin skin test (TST) positive (group A controls), and 21 controls were TST positive and/or had previously been vaccinated with BCG (group B controls). Study subjects were drawn from one hospital and one primary health care unit in Rio de Janeiro City, Brazil. One version of the test (ICT-1) was evaluated by using whole blood, plasma, and serum samples. Sera obtained for this study were frozen and later tested with a manufacturer-modified version of the test (ICT-2). Among the patients suspected of having PTB, the sensitivities of the ICT-1 with whole blood, serum, and plasma were 83, 65, and 70%, respectively, and the specificities were 46, 67, and 56%, respectively. Among the group A controls, the specificities of ICT-1 with the three specimen types were 95, 100, and 95%, respectively. Among the group B controls, the specificities of ICT-1 with the three specimen types were 71, 86, and 86%, respectively. Among the patients suspected of having PTB, the sensitivity of ICT-2 was 70% and the specificity was 65%. Among the group A controls, the specificity of ICT-2 was 95%, and among the group B controls, the specificity of ICT-2 was 81%. With a 29% observed prevalence of PTB among patients suspected of having PTB, the positive predictive values of the ICT tests ranged from 39 to 50% and the negative predictive values ranged from 82 to 87%. The ICT Tuberculosis tests were not sufficiently predictive to warrant their widespread use as routine diagnostic tests for PTB in this setting. However, further evaluation of these tests in specific epidemiologic settings may be warranted

    Undiagnosed tuberculosis among HIV clinic attendees: association with antiretroviral therapy and implications for intensified case finding, isoniazid preventive therapy, and infection control.

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    OBJECTIVES: Initiation of antiretroviral therapy (ART) and the 3I's are strategies to prevent HIV-associated tuberculosis (TB). We describe factors associated with undiagnosed TB among HIV-infected patients attending an HIV clinic in South Africa and discuss implications for the 3 Is. DESIGN: Convenience sample of HIV clinic attendees. METHODS: HIV-infected participants were assessed for TB using a symptom screen, sputum-smear microscopy, sputum and blood mycobacterial culture, fine needle aspiration of enlarged lymph nodes, and chest radiography. RESULTS: Four hundred twenty-two participants were enrolled. The median age and CD4+ T-cell count were 37 years [interquartile range (IQR): 31-44 years] and 215 cells per microliter (IQR: 107-347 cells/μL). Forty-seven percent had been on ART for a median duration of 8 months (IQR: 3.3-22.8 months). Three hundred sixty-one participants (85.6%) reported TB symptoms. Twenty-seven participants (6.4%) met criteria for bacteriologically confirmed TB and 50 (11.6%) for any form of TB. Bacteriologically confirmed TB was associated with CD4+ T-cell counts ≤100 cells per microliter (odds ratio: 5.05, 95% confidence interval: 1.69 to 15.12) when compared with CD4+ T-cell counts >200 cells per microliter and hemoglobin {hemoglobin < 10 g/dL [odds ratio 3.12 (95% confidence interval: 1.26 to 7.72)]}. CONCLUSIONS: Undiagnosed TB among HIV-infected ambulatory patients was associated with low CD4+ T-cell counts regardless of ART status. TB screening algorithms which include CD4+ T-cell count and hemoglobin testing may be an effective way to identify HIV-infected clinic attendees at highest risk of undiagnosed TB. Isoniazid preventive therapy and TB infection control are essential for reducing occurrence of HIV-associated TB even after ART initiation

    Diagnostic accuracy of a urine lipoarabinomannan enzyme-linked immunosorbent assay for screening ambulatory HIV-infected persons for tuberculosis.

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    OBJECTIVE: To assess the diagnostic accuracy of the urine lipoarabinomannan (LAM) test among ambulatory HIV-infected persons. DESIGN: Cross-sectional. METHODS: HIV-infected persons consecutively presenting to the HIV Clinic at Tembisa Main Clinic in Ekhuruleni, South Africa, were screened for symptoms of tuberculosis (TB) and asked to provide sputum and blood samples for smears for acid-fast bacilli and mycobacterial culture and a urine specimen for a LAM enzyme-linked immunosorbent assay. Fine needle aspirates were obtained from participants with enlarged lymph nodes and sent for histopathology. Nonpregnant participants underwent chest x-ray. RESULTS: : Four hundred twenty-two HIV-infected participants were enrolled with median age 37 years (interquartile range: 31-44 years), median CD4+ T-cell count 215 cells per microliter (interquartile range: 107-347 cells/μL), and 212 (50%) receiving antiretroviral therapy. Thirty (7%) had active TB: 18 with only pulmonary TB, 5 with only extrapulmonary TB, and 7 with both pulmonary TB and extrapulmonary TB. Twenty-seven percent [95% confidence interval (CI): 12% to 48%] of TB cases were sputum acid-fast bacilli positive. The sensitivity and specificity of the urine LAM compared with the gold standard of positive bacteriology or histopathology were 32% (95% CI: 16% to 52%) and 98% (95% CI: 96% to 99%), respectively. Urine LAM had higher sensitivity in TB cases with higher bacillary burdens, though these differences were not statistically significant. CONCLUSIONS: The sensitivity of urine LAM testing is inadequate to replace mycobacterial culture. In contrast to prior research on the urine LAM, this study was conducted among less sick, ambulatory HIV-infected patients presenting for routine care
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