Performance of symptom-based tuberculosis screening among people living with HIV: not as great as hoped.

OBJECTIVE: The objective of the present study was to determine the diagnostic performance of the symptom-based tuberculosis (TB) screening questionnaire recommended by WHO for people living with HIV (PLWH) in resource-limited settings, among adults off and on antiretroviral therapy (ART). DESIGN: Cross-sectional study at two HIV clinics in South Africa. METHODS: A total of 825 PLWH completed the screening questionnaire and underwent investigations [chest radiography (CXR) and microbiologic testing of sputa]. A positive screen was defined as presence of cough, fever, night sweats, or weight loss. Pulmonary tuberculosis (PTB) was defined as sputum smear positive for acid-fast bacilli or growth of Mycobacterium tuberculosis. RESULTS: Of 737 participants with at least one diagnostic sputum specimen, PTB was diagnosed in 31 of 522 (5.9%) on ART, and 34 of 215 (15.8%) not on ART. The questionnaire missed 15 of 31 (48.4%) PTB cases on ART, and three of 34 (8.8%) not on ART. Among participants on ART, post-test probability of PTB diagnosis (95% confidence interval) was 6.8% (4.0-10.9%) if screening positive, and 5.2% (2.9-8.4%) if screening negative, whereas among participants not on ART, post-test probabilities were 20.3% (14.2-27.5%) and 4.8% (1.0-13.5%), respectively. Among participants diagnosed with PTB, those on ART were significantly less likely to screen positive (adjusted odds ratio 0.04, 95% confidence interval: 0.01-0.39). In both groups (ART and no ART), screening was more sensitive when CXR was incorporated. CONCLUSION: For case detection and exclusion of PTB, the WHO-recommended questionnaire performed adequately among PLWH not on ART, and poorly among those on ART. Further research is needed to identify feasible and effective TB screening strategies for PLWH in resource-limited settings.