Association between tuberculosis and HIV disease progression in a high tuberculosis prevalence area

SETTING: Adult human immunodeficiency virus (HIV) clinics affiliated to the University of Cape Town, South Africa. OBJECTIVE: To assess the impact of tuberculosis on HIV-1 discase progressio n in an area with high tuberculosis prevalence and minimal antiretroviral t herapy use. DESIGN: Prospective patient cohort study. METHODS: Age, race, risk status, CD4+ T-lymphocyte count, history of AIDS, prophylactic co-trimoxazole and antiretroviral therapy were controlled for in a time-dependent Cox proportional hazards regression model. RESULTS: Tuberculosis fulfilling the case definition developed in 158/609 p atients in the 5-year observation period. Tuberculosis was associated with an increased risk of AIDS (adjusted risk ratio [RR] = 1.60, 95% confidence interval [CI] 1.08-2.41; P = 0.02) and death (adjusted RR = 2.16, 95%CI 1.2 9-3.59; P = 0.003). In a stratified analysis, the increased mortality assoc iated with tuberculosis was observed only in patients with CD4+ T-lymphocyt e count >200 cells/mul and in those without AIDS at baseline. CONCLUSION: The onset of tuberculosis in HIV-infected patients is associate d with an increased risk of AIDS and death. Although a causal link cannot b e established in an observational study, our findings support the view that prolonged immune activation induced by tuberculosis leads to prolonged inc reased HIV replication and consequent accelerated disease progression.