Impact of combination antiretroviral therapy on the risk of tuberculosis among persons with HIV infection

Abstract

To assess the association between use of different antiretroviral regimens and incidence of tuberculosis among HIV-infected individuals. Observational, multicenter, prospective cohort study. Twenty-eight infectious diseases hospital units in Italy. A total of 2160 HIV-infected persons were considered for enrolment in a study on the implementation of tuberculosis preventive therapy between 1 May 1995 and 30 April 1996. The 1360 subjects who completed tuberculin screening at base-line were included in this analysis. Information on the use of antiretroviral therapies over time was collected. The median duration of follow-up was 104 weeks and 997 subjects (73.3%) completed the study. Incidence of active tuberculosis according to different types of antiretroviral therapy. Eighteen cases of tuberculosis were observed with an overall incidence rate of 0.79 per 100 person–years of observation [95% confidence interval (CI), 0.51–1.31]. Tuberculin positivity and low CD4+ lymphocyte count were the only base-line variables independently associated with the risk of tuberculosis. During follow-up, 637 patients took double combination antiretroviral therapy and 387 took triple combination therapy. After adjusting for base-line characteristics of enrolled individuals, the relative hazard of tuberculosis was 0.16 (95% CI, 0.03–0.74) for double combination therapy and 0.08 (95% CI, 0.01–0.88) for triple combination therapy compared with no therapy or monotherapy. Combination antiretroviral therapy significantly reduced the risk of tuberculosis in HIV-infected persons. In industrialized countries, the widespread use of this treatment may determine a decrease in the incidence of HIV-associated tuberculosis, possibly contributing to a reduction in the overall incidence of tuberculosis.