Background: Tuberculosis is a common complication and leading cause of death in HIV infection. Antiretroviral therapy (ART) lowers the risk of tuberculosis, but may not be sufficient to control HIV-related tuberculosis. Isoniazid preventive therapy (IPT) reduces tuberculosis incidence significantly, but is not widely used.
Methods: We analysed tuberculosis incidence in 11 026 HIV-infected patients receiving medical care at 29 public clinics in Rio de Janeiro, Brazil, between 1 September 2003 and 1 September 2005. Data were collected through a retrospective medical record review. We determined rates of tuberculosis in patients who received neither ART nor IPT, only ART, only IPT, or both ART and IPT.
Results: The overall tuberculosis incidence was 2.28 cases/100 person-years (PY) [95% confidence interval (CI) 2.06–2.52]. Among patients who received neither ART nor IPT, incidence was 4.01/100 PY. Patients who received ART had an incidence of 1.90/100 PY (95% CI 1.66–2.17) and those treated with IPT had a rate of 1.27/100 PY (95% CI 0.41–2.95). The incidence among patients who received ART and IPT was 0.80/100 PY (95% CI 0.38–1.47). Multivariate Cox proportional hazards modeling revealed a 76% reduction in tuberculosis risk among patients receiving both ART and IPT (adjusted relative hazard 0.24; P < 0.001) after adjusting for age, previous tuberculosis diagnosis, and CD4 cell counts at baseline.
Conclusion: The use of both IPT and ART in HIV-infected patients is associated with significantly reduced tuberculosis incidence. In conjunction with expanded access to ART, the wider use of IPT in patients with HIV will improve tuberculosis control in high burden areas.
From the aCenter for Tuberculosis Research and Departments of Medicine and International Health, Johns Hopkins University, Baltimore, Maryland, USA
bMunicipal Health Secretariat, Rio de Janeiro, Brazil
cFiocruz, Rio de Janeiro and Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Received 12 February, 2007
Revised 14 March, 2007
Accepted 15 March, 2007
Correspondence to Richard E. Chaisson, MD, Center for Tuberculosis Research, 1550 Orleans Street, 1M.08, Baltimore, MD 21231, USA. Tel: +1 410 955 1755; e-mail: firstname.lastname@example.org