Effect of pulmonary tuberculosis on mortality in patients receiving HAART.

Objective: To estimate the effect of ongoing treatment for pulmonary tuberculosis (PTB) at time of initiation of HAART on subsequent risk of death.

Design: Evaluation of an open cohort of 7512 patients who initiated HAART between April 2004 and March 2007 in the Themba Lethu Clinic in Johannesburg, South Africa.

Methods: Mortality hazard ratios were estimated using marginal structural Cox proportional hazards models to control for bias due to both confounding and loss to follow-up. Extensive sensitivity and secondary analyses were performed.

Results: Although the crude hazard ratio for mortality in HAART-treated patients comparing those with and without treated PTB was 1.71 (95% confidence interval 1.31-2.23), the adjusted hazard ratio was 1.06 (95% confidence interval 0.75-1.49), indicating no difference in mortality risk. Similar effects were found when we considered different durations of time between initiation of PTB treatment and HAART, and sensitivity analysis confirmed main results. Secondary analysis suggested that individuals with PTB and other risk factors for death might be at particularly high risk of death during HAART treatment.

Conclusion: The increase in death that we observed among individuals with PTB at the time of HAART initiation appears not to be due to the to the presence of PTB, but instead to confounding factors such as low CD4 cell count, low BMI, and WHO stage IV disease. These results further demonstrate that initiation of HAART soon after initiation of PTB treatment is not likely to put patients at higher risk of death.