Diagnosis of pulmonary tuberculosis among asymptomatic HIV+ patients in Guangxi, China

Background Pulmonary tuberculosis (PTB) among asymptomatic Chinese patients with HIV infection has not been investigated despite high tuberculosis burden in China. This study was aimed to evaluate the prevalence, risk factors and clinical outcomes of PTB among asymptomatic patients with HIV/AIDS in Guangxi to facilitate the development of diagnostic and treatment strategies.Methods All asymptomatic adult HIV-infected patients with CD4 ＜350 cells/μl who attended four HIV clinics in Guangxi between August 2006 and March 2008 were evaluated for active PTB with physical examination, chest X-ray (CXR),sputum smear and/or sputum liquid culture. Data were described using median (interquartile range, IQR) and frequencies.Univariate and multivariate Logistic regression analyses were performed to identify risk factors associated with PTB.Results Among 340 asymptomatic subjects, 15 (4%) were diagnosed with PTB, with 4 (27%) sputum smear positive and 8 (53%) sputum culture positive. CXR has higher diagnostic sensitivity (87%) than sputum smear (25%) and sputum culture (67%), but lower specificity (56%) compared with sputum smear (99%) and culture (100%). In univariate analysis,injection drug user, body mass index (BMI) ＜18 kg/m2, CD4 ＜50 cells/μl and presence of peripheral lymphadenopathy were associated with an increased risk of asymptomatic PTB, while in multivariate analysis only peripheral lymphadenopathy maintained statistical significance (OR=7.6, 95% CI 1.4-40). Patients with negative smear and minor or no abnormalities on CXR had longer interval between screening and TB treatment.Conclusions PTB was relatively common in this group of HIV+ asymptomatic Chinese patients. Diagnosis is challenging especially where sputum culture is unavailable. These findings suggest that an enhanced evaluation for PTB needs to be integrated with HIV care in China and transmission prevention in China to control at both households and health care facilities, especially for patients with factors associated with a higher risk of PTB.