Does tuberculosis increase HIV load?

Background: The effect that tuberculosis (TB) has on human immunodeficiency virus (HIV) disease progression is not clearly understood.

Methods: In an observational cohort study of HIV-infected adults in South Africa, baseline and final HIV load were compared between individuals who experienced an episode of TB (n=30) during follow-up and control subjects (n=56) matched by baseline CD4 cell count and follow-up time; linear regression modeling was used to control for confounding.

Results: Mean HIV load was higher in the TB group than in the non-TB control group for both baseline (4.73 vs. 4.24 log(10) copies/mL; P=.003) and final values (5.02 vs. 4.34 log(10) copies/mL; P<.001). After adjustment for baseline HIV load and World Health Organization HIV stage, the difference in final HIV load was 0.24 log(10) copies/mL (95% confidence interval, -0.01 to 0.50 log(10) copies/mL; P=.06).

Conclusions: Poor prognosis for HIV-infected individuals after TB may be due to preexisting high HIV load rather than to the TB event itself. An episode of TB was associated with a small adjusted increase in HIV load at the end of the study--an increase that would not be regarded as clinically significant in an individual but could have some effect on HIV disease progression or HIV transmission at the population level. Prevention of TB is important for the reduction of HIV-related morbidity and mortality; however, antiretroviral therapy is required to have a major effect on survival in individuals with HIV disease.