Latent and subclinical tuberculosis in HIV infected patients: a cross-sectional study
Abstract (provisional)
Background
HIV and tuberculosis (TB) are commonly associated. Identifying latent and asymptomatic tuberculosis infection in HIV-positive patients is important in preventing death and morbidity associated with active TB.
Methods
Cross-sectional study of one time use of an interferon-gamma release assay (T-SPOT.TB - immunospot) to detect tuberculosis infection in patients in an inner city HIV clinic with a large sub-Saharan population.
Results
542 patient samples from 520 patients who had disclosed no symptoms of TB were screened. Median follow-up was 35 months (range 27-69). More than half (55%) originated from countries with medium or high tuberculosis burden and 57% were women. Antiretroviral therapy was used by 67%; median CD4 count at test was 458 cells/ul. A negative test was found in 452 and an indeterminate results in 40 (7.4%) but neither were associated with a low CD4 count. A positive test was found in 50 individuals. All patients with positive tests were referred to the TB specialist, 47 (94%) had a chest radiograph and 46 (92%) attended the TB clinic. Two had culture-positive TB and a third individual with features of active TB was treated. 40 started and 38 completed preventive treatment. One patient who completed preventive treatment with isoniazid monotherapy subsequently developed isoniazid-resistant pulmonary tuberculosis. No patient with a negative test has developed TB.
Conclusions
The T-SPOT.TB test helped identify active TB in those without symptoms. There was a high completion rate for preventive treatment in those with a positive test result.
