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. 2011 Apr 6;6(4):e18502.
doi: 10.1371/journal.pone.0018502.

Evaluation of the 2007 WHO guideline to improve the diagnosis of tuberculosis in ambulatory HIV-positive adults

Olivier Koole  1 , Sopheak Thai, Kim Eam Khun, Reaksmey Pe, Johan van Griensven, Ludwig Apers, Jef Van den Ende, Tan Eang Mao, Lutgarde Lynen
Affiliations

Evaluation of the 2007 WHO guideline to improve the diagnosis of tuberculosis in ambulatory HIV-positive adults

Olivier Koole et al. PLoS One. .

Abstract

Background: In 2007 WHO issued a guideline to improve the diagnosis of smear-negative and extrapulmonary tuberculosis (EPTB) in HIV-positive patients. This guideline relies heavily on the acceptance of HIV-testing and availability of chest X-rays.

Methods and findings: Cohort study of TB suspects in four tuberculosis (TB) clinics in Phnom Penh, Cambodia. We assessed the operational performance of the guideline, the incremental yield of investigations, and the diagnostic accuracy for smear-negative tuberculosis in HIV-positive patients using culture positivity as reference standard. 1,147 (68.9%) of 1,665 TB suspects presented with unknown HIV status, 1,124 (98.0%) agreed to be tested, 79 (7.0%) were HIV-positive. Compliance with the guideline for chest X-rays and sputum culture requests was 97.1% and 98.3% respectively. Only 35 of 79 HIV-positive patients (44.3%) with a chest X-ray suggestive of TB started TB treatment within 10 days. 105 of 442 HIV-positive TB suspects started TB treatment (56.2% smear-negative pulmonary TB (PTB), 28.6% smear-positive PTB, 15.2% EPTB). The median time to TB treatment initiation was 5 days (IQR: 2-13 days), ranging from 2 days (IQR: 1-11.5 days) for EPTB, over 2.5 days (IQR: 1-4 days) for smear-positive PTB to 9 days (IQR: 3-17 days) for smear-negative PTB. Among the 34 smear-negative TB patients with a confirmed diagnosis, the incremental yield of chest X-ray, clinical suspicion or abdominal ultrasound, and culture was 41.2%, 17.6% and 41.2% respectively. The sensitivity and specificity of the algorithm to diagnose smear-negative TB in HIV-positive TB suspects was 58.8% (95%CI: 42.2%-73.6%) and 79.4% (95%CI: 74.8%-82.4%) respectively.

Conclusions: Pending point-of-care rapid diagnostic tests for TB disease, diagnostic algorithms are needed. The diagnostic accuracy of the 2007 WHO guideline to diagnose smear-negative TB is acceptable. There is, however, reluctance to comply with the guideline in terms of immediate treatment initiation.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Inclusion criteria and screening questions for TB suspects*.
Figure 2
Figure 2. WHO algorithm for the diagnosis of tuberculosis in ambulatory HIV-positive patients.
Figure 3
Figure 3. Operational performance of the WHO 2007 algorithm for the diagnosis of tuberculosis in ambulatory HIV-positive patients (diagnostic pathway and treatment recommendation).
Figure 4
Figure 4. Diagnostic performance of the WHO guideline in the smear-negative cohort of TB suspects (reference: positive sputum culture).
Figure 5
Figure 5. Distribution of TB categories among HIV-positive patients started on TB treatment.
See this image and copyright information in PMC

References

    1. WHO. Global Tuberculosis Control: a short update to the 2009 report. 2009;17 Available: http://www.who.int/tb/publications/global_report/2009/update/tbu_9.pdf. Accessed: 2010 Nov.
    1. WHO. Global Tuberculosis Control 2009. 2009;17 Available: http://www.who.int/tb/publications/global_report/2009/pdf/full_report.pdf. Accessed: 2010 Nov.
    1. National AIDS Authority. UNGASS Country Progress Report Cambodia. 2008;17 Available: http://data.unaids.org/pub/Report/2008/cambodia_2008_country_progress_re.... Accessed: 2010 Nov.
    1. Ministry of Health Cambodia. Tuberculosis Report 2008
    1. Corbett EL, Watt CJ, Walker N, Maher D, Williams BG, et al. The growing burden of tuberculosis: global trends and interactions with the HIV epidemic. Arch Intern Med. 2003;163:1009–1021. - PubMed

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