Infections with Mycobacterium tuberculosis and Mycobacterium avium among HIV-infected patients after the introduction of highly active antiretroviraltherapy

The impact of highly active antiretroviral therapy (HAART) among human immu nodeficiency virus (HIV)-infected patients on the incidences of mycobacteri al infections has not been studied in detail. We assessed incidences of myc obacterial diseases among HIV-infected patients following the introduction of HAART, using data from the EuroSIDA study, a European, multicenter obser vational cohort of more than 7,000 patients. Overall incidences of Mycobact erium tuberculosis (TB) and Mycobacterium avium complex (MAC) were 0.8 and 1.4 cases/100 person-years of follow-up (PYF), decreasing from 1.8 (TB) and 3.5 cases/100 PYF (MAC) before September 1995 to 0.3 and 0.2 cases/100 PYF after March 1997. After adjustment for changes in CD4 cell count and use o f antiretroviral treatment in Cox proportional hazards models, the risk of MAC decreased with increasing calendar time (hazard ratio per calendar year ; HR = 0.58 [95% confidence intervals: 0.45-0.74], whereas this was not the case for TB; 0.95 [0.74-1.22]). In conclusion, we documented marked decrea ses in the incidence of TB and to an even larger extent of MAC among HIV-in fected patients from 1994 to 1999. The decrease in TB was associated with t he introduction of HAART and changes in CD4 cell count. These factors could also explain some of the decrease in MAC over time, though there remained a significantly lower risk of MAC than expected.