Clinical and radiographic factors do not accurately diagnose smear-negative tuberculosis in HIV-infected inpatients in Uganda: a cross-sectional study.
BACKGROUND
Although World Health Organization guidelines recommend clinical judgment and chest radiography for diagnosing tuberculosis in HIV-infected adults with unexplained cough and negative sputum smears for acid-fast bacilli, the diagnostic performance of this approach is unknown. Therefore, we sought to assess the accuracy of symptoms, physical signs, and radiographic findings for diagnosing tuberculosis in this population in a low-income country with a high incidence of tuberculosis.


METHODS
We performed a cross-sectional study enrolling consecutive HIV-infected inpatients with unexplained cough and negative sputum smears for acid-fast bacilli at Mulago Hospital in Kampala, Uganda. Trained medical officers prospectively collected data on standard symptoms and signs of systemic respiratory illness, and two radiologists interpreted chest radiographs in a standardized fashion. We calculated positive- and negative-likelihood ratios of these factors for diagnosing pulmonary tuberculosis (defined when mycobacterial cultures of sputum or bronchoalveolar lavage fluid were positive). We used both conventional and novel regression techniques to develop multivariable prediction models for pulmonary tuberculosis.


RESULTS
Among 202 enrolled HIV-infected adults with negative sputum smears for acid-fast bacilli, 72 (36%) had culture-positive pulmonary tuberculosis. No single factor, including respiratory symptoms, physical findings, CD4+ T-cell count, or chest radiographic abnormalities, substantially increased or decreased the likelihood of pulmonary tuberculosis. After exhaustive testing, we were also unable to identify any combination of factors which reliably predicted bacteriologically confirmed tuberculosis.


CONCLUSIONS
Clinical and radiographic criteria did not help diagnose smear-negative pulmonary tuberculosis among HIV-infected patients with unexplained cough in a low-income setting. Enhanced diagnostic methods for smear-negative tuberculosis are urgently needed.
Davis
J Lucian
JL
Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America. lucian.davis@ucsf.edu
Worodria
William
W
Kisembo
Harriet
H
Metcalfe
John Z
JZ
Cattamanchi
Adithya
A
Kawooya
Michael
M
Kyeyune
Rachel
R
den Boon
Saskia
S
Powell
Krista
K
Okello
Richard
R
Yoo
Samuel
S
Huang
Laurence
L
D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D003371:Cough / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D007297:Inpatients; D008297:Male; D008853:Microscopy / Q000379:methods; D011859:Radiography; D011871:Radiology / Q000379:methods; D012044:Regression Analysis; D015203:Reproducibility of Results; D014397:Tuberculosis, Pulmonary / Q000150:complications* / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D014454:Uganda