People receiving treatment for pulmonary TB are no more likely to die if they start antiretroviral treatment than their counterparts without TB, according to findings from South Africa presented today at the Fifteenth Conference on Retroviruses and Opportunistic Infections in Boston. The only exception to this finding is malnourished people with TB who start ART less than 30 days after starting TB treatment.
The study was carried out because there are conflicting data from resource-limited settings regarding the impact of active tuberculosis on the risk of death in HIV-positive patients starting antiretroviral therapy.
To gain a better understanding of this issue investigators from the University of North Caroline School of Public Health and the Themba Lethu Clinic in Johannesburg performed a retrospective study. They wanted to see if patients with active tuberculosis when they started anti-HIV treatment had an increased risk of death or loss to follow-up (for reasons other than transferring care to another HIV treatment centre) than tuberculosis-free patients.
The study ran between April 2004 and August 2007. Of the 7519 clinic patients who started antiretroviral therapy during this period, 1202 (16%) had active tuberculosis and were included in the investigators’ analysis. Of these patients, 284 received tuberculosis treatment for 30 days or less before anti-HIV treatment was started.
HIV disease status was worse in patients with active tuberculosis than the patients who did not have tuberculosis at the time antiretroviral therapy was started. CD4 cell counts (77 cells/mm3 vs. 113 cells/mm3, p
Overall there was no difference in the risk of death or loss to follow-up for patients with or without active tuberculosis in the twelve months after anti-HIV therapy was initiated.
Multivariate analysis showed that there was a significantly elevated risk of death only in the group of patients at greatest risk of HIV disease progression: those with a CD4 cell count below 50 cells/mm3 and those with a low body mass index (BMI below 18.5m2).
This analysis showed that patients receiving fewer than 30 days of tuberculosis therapy who had a low body mass index were significantly more likely to die or be lost to follow-up than non-tuberculosis patients with a low body mass index (incidence rate ratio [IRR] = 5.6; 95% CI, 2.46 – 12.74). Furthermore, patients who received over 30 days of therapy for active tuberculosis before initiating antiretroviral therapy and who had a very low CD4 cell count were significantly more likely to have a poor outcome than tuberculosis-free patients starting anti-HIV treatment with a CD4 cell count below 50 cells/mm3 (IRR = 4.26; 95% CI, 2.42 – 7.47).
“Our results suggest that individuals receiving tuberculosis treatment are not at increased risk of death after [antiretroviral therapy] initiation”, comment the investigators. They add, however, “individuals with additional risk factors, such as low body mass index and low CD4 counts may have substantially increased risks.”
Westreich D et al. The influence of TB on early mortality in the Themba Lethu clinical cohort, Johannesburg, South Africa. Fifteenth Conference on Retroviruses and Opportunistic Infections, Boston. Abstract 145, 2008.