Active case finding for pulmonary tuberculosis using mobile digital chest radiography: an observational study

• Published in: The international journal of tuberculosis and lung disease Vol. 16; no. 11; pp. 1461 - 1467
• Main Authors: Story, A., Aldridge, R. W., Abubakar, I., Stagg, H. R., Lipman, M., Watson, J. M., Hayward, A. C.
• Format: Journal Article
• Language: English
• Published: Paris, France International Union Against Tuberculosis and Lung Disease 01-11-2012; International Union against Tuberculosis and Lung Disease
• Subjects: Adolescent; Adult; Bacterial diseases; Bacterial diseases of the respiratory system; Biological and medical sciences; Female; Hard To Reach; Homeless Persons; Human bacterial diseases; Humans; Impact; Infectious diseases; Logistic Models; London - epidemiology; Male; Mass Screening - methods; Medical sciences; Mobile Health Units; Mycobacterium; Pneumology; Prisoners; Radiographic Image Enhancement - methods; Radiography, Thoracic - methods; Sensitivity; Sensitivity and Specificity; Specificity; Sputum - microbiology; Substance Abuse Treatment Centers; Tuberculosis; Tuberculosis and atypical mycobacterial infections; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - diagnostic imaging; Tuberculosis, Pulmonary - epidemiology; Young Adult; British Isles, England, Greater London, London; Human; Lung disease; Radiodiagnosis; Respiratory disease; Pulmonary tuberculosis; impact; tuberculosis; Thorax; Mycobacterial infection; hard to reach; Infection; Case study; Sensitivity; Specificity; Bacteriosis; Medical imagery; Digital radiography; Pneumology
• ISSN: 1027-3719; 1815-7920
• DOI: 10.5588/ijtld.11.0773

BACKGROUND: Mobile digital chest radiography (CXR) is used routinely to screen for pulmonary tuberculosis (PTB) in London among homeless populations, persons accessing drug treatment services and prisoners.OBJECTIVE: 1) To establish the sensitivity and specificity of mobile digital
CXR, and 2) to test the hypothesis that actively identified cases have reduced odds of sputum smear positivity vs. those presenting passively to health care services from the same populations.METHODS: Sensitivity and specificity were calculated using a gold standard comparator of culture-confirmed
cases of PTB reported to the national surveillance system within 90 days of screening. Logistic regression was used to determine whether actively detected cases had reduced odds of smear positivity compared to passively detected cases after adjustment for confounding.RESULTS: The intervention
had a sensitivity of 81.8% (95%CI 64.5-93.0) and a specificity of 99.2% (95%CI 99.1-99.3). After adjusting for confounding, there was evidence that cases identified through screening were less likely to be smear-positive than passively identified cases (OR 0.34, 95%CI 0.14-0.85;
likelihood ratio test P = 0.022).CONCLUSION: Digital CXR achieves a high level of sensitivity and specificity in an operational setting; targeted mobile radiographic screening can reduce the risk of onward transmission by identifying cases before they become infectious.