Extrapulmonary tuberculosis (EPTB) is difficult to confirm bacteriologically and requires specific diagnostic capacities. We studied diagnostic modalities and clinical outcomes of EPTB compared to pulmonary tuberculosis (PTB) among HIV-positive adults.
We collected patient data from HIV/TB co-infected adults (≥16 years) from antiretroviral (ART) programs participating in the IeDEA network in Africa, Asia/Pacific and Central/South America between 2012 and 2014. We categorized TB as PTB (dominant site) and EPTB only. We used multivariable logistic regression to assess association of 1) clinical factors with EPTB and 2) EPTB with clinical outcomes, adjusted for age, sex, history of TB, CD4 cell counts, considering sites heterogeneity.
We analysed 2,751 HIV/TB co-infected adults. The median age was 38 years (interquartile range [IQR] 32-45); 1,129 (41%) were female. Of these, 2,103 (76%) had PTB and 648 (24%) EPTB only (Table). At TB treatment start, patients with EPTB had lower median CD4 cell counts compared to PTB (105 vs. 118 cells/µl). Among EPTB patients, the most frequently involved organs were lymph nodes (25%), pleura (15%), abdomen (11%), and meninges (7%, Table). Available diagnostic tests were less frequently used in EPTB compared to PTB patients (58% vs. 80%), whereas in all other cases diagnosis was made based on clinical symptoms. Among EPTB patients, smear microscopy was the most commonly used diagnostic test (49%), followed by culture (13%), and Xpert (3%). Bacteriologic confirmation (culture, smear, Xpert, other molecular tests) was obtained in 837 (40%) of PTB, but only in 103 (16%) of EPTB cases; with the highest proportions of confirmed cases in lymph nodes (30%), meninges (19%), abdomen (14%), joint/bones (11%), pleura (13%), and others (13%). Among patients with CD4 <50 cells/µL, the risk of EPTB was significantly higher than PTB (adjusted odd ratio [aOR] 1.3, 95% confidence interval [CI] 1.1-1.6). EPTB overall was not associated with higher mortality compared to PTB (aOR 1.0, 95% Cl 0.7-1.6), but meningitis was (aOR 2.1, 95% CI 1.3-3.3). Successful outcomes (cured/treatment completed) were as frequent among EPTB compared to PTB cases (aOR 1.1, 95% Cl 0.8-1.3).
Diagnosis of EPTB at ART programs in lower income countries was mainly based on clinical symptoms. Strengthening of diagnostic services is needed to improve clinical management of EPTB, particularly in patients with low CD4 cell counts and severe forms.