Journal Article

The Risk and Timing of Tuberculosis Diagnosed in Smear-Negative TB Suspects: A 12 Month Cohort Study in Harare, Zimbabwe

Corbett, Elizabeth L., Rusikaniko, Simba, Fielding, Katherine, Mason, Peter R., MacPherson, Peter, Bandason, Tsitsi, Munyati, Shungu S., Mungofa, Stanley, Dimairo, Munyaradzi, Butterworth, Anthony E., Zezai, Abbas

2010

Overview

Cases of smear-negative TB have increased dramatically in high prevalence HIV settings and pose considerable diagnostic and management challenges. Between February 2006 and July 2007, a cohort study nested within a cluster-randomised trial of community-based case finding strategies for TB in Harare, Zimbabwe was undertaken. Participants who had negative sputum smears and remained symptomatic of TB were follow-up for one year with standardised investigations including HIV testing, repeat sputum smears, TB culture and chest radiography. Defaulters were actively traced to the community. The objectives were to investigate the incidence and risk factors for TB. TB was diagnosed in 218 (18.2%) participants, of which 39.4% was bacteriologically confirmed. Most cases (84.2%) were diagnosed within 3 months, but TB incidence remained high thereafter (111.3 per 1000 person-years, 95% CI: 86.6 to 146.3). HIV prevalence was 63.3%, and HIV-infected individuals had a 3.5-fold higher risk of tuberculosis than HIV-negative individuals. We found that diagnosis of TB was insensitive and slow, even with early radiography and culture. Until more sensitive and rapid diagnostic tests become widely available, a much more proactive and integrated approach towards prompt initiation of ART, ideally from within TB clinics and without waiting for TB to be excluded, is needed to minimise the risk and consequences of diagnostic delay.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Antiretroviral drugs / Cohort analysis / Cohort Studies / Communities / Diagnostic imaging / Diagnostic systems / Health risks / HIV / HIV Infections - complications / HIV Infections - epidemiology / HIV tests / Human immunodeficiency virus / Incidence / Infectious Diseases/HIV Infection and AIDS / Infectious Diseases/Respiratory Infections / Medical diagnosis / Medical research / Mortality / Public Health and Epidemiology / Public Health and Epidemiology/Epidemiology / Public Health and Epidemiology/Global Health / Public Health and Epidemiology/Infectious Diseases / Radiography / Risk analysis / Risk factors / Smear / Sputum / Sputum - microbiology / Time Factors / Tuberculosis / Tuberculosis - diagnosis / Tuberculosis - epidemiology / Zimbabwe