Clinical predictors and accuracy of empiric tuberculosis treatment among sputum smear-negative HIV-infected adult TB suspects in Uganda

PLoS One. 2013 Sep 6;8(9):e74023. doi: 10.1371/journal.pone.0074023. eCollection 2013.

Abstract

Introduction: The existing diagnostic algorithms for sputum smear-negative tuberculosis (TB) are complicated, time-consuming, and often difficult to implement. The decision to initiate TB treatment in resource-limited countries is often largely based on clinical predictors. We sought to determine the clinical predictors and accuracy of empiric TB treatment initiation in HIV-infected sputum smear-negative TB suspects using sputum culture as a reference standard.

Setting: Out-patient HIV-TB integrated urban clinic in Kampala, Uganda.

Methods: HIV-infected TB suspects were screened using sputum smear microscopy, and mycobacterial sputum liquid and solid cultures were performed. Smear results were made available to the clinician who made a clinical decision on empiric TB treatment initiation for sputum smear-negative patients. Clinic records were reviewed for patients whose sputum smears were negative to collect data on socio-demographics, TB symptomatology, chest X-ray findings, CD4 cell counts and TB treatment initiation.

Results: Of 253 smear-negative TB suspects, 56% (142/253) were females, median age 38 IQR (31-44) years, with a median CD4 cell count of 291 IQR (150-482) cells/mm(3). Of the 85 (33.6%) smear-negative patients empirically initiated on TB treatment, 35.3% (n = 30) were sputum culture positive compared to only 18 (10.7%) of the 168 untreated patients (p<0.001). Abnormal chest X-ray [aOR 10.18, 95% CI (3.14-33.00), p<0.001] and advanced HIV clinical stage [aOR 3.92, 95% CI (1.20-12.85), p = 0.024] were significantly associated with empiric TB treatment initiation. The sensitivity and specificity of empiric TB treatment initiation in the diagnosis of TB in HIV-infected patients after negative smear microscopy was 62.5% and 73.7% respectively.

Conclusion: In resource-limited settings, clinically advanced HIV and abnormal chest X-ray significantly predict a clinical decision to empirically initiate TB treatment in smear-negative HIV-infected patients. Empiric TB treatment initiation correlates poorly with TB cultures. Affordable, accurate and rapid point-of-care diagnostics are needed in resource-limited settings to more accurately determine which HIV-infected TB suspects have smear-negative TB.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antitubercular Agents / therapeutic use*
  • Coinfection
  • Female
  • HIV Infections / diagnosis
  • Humans
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / isolation & purification*
  • Outcome Assessment, Health Care
  • Prognosis
  • Sputum / microbiology*
  • Tuberculosis / diagnosis*
  • Tuberculosis / drug therapy*
  • Uganda

Substances

  • Antitubercular Agents