Post-tuberculosis (TB) lung disease is common in patients with human immunodeficiency virus (HIV)-associated TB at high risk for TB-associated immune reconstitution inflammatory syndrome (TB-IRIS), according to study results published in the European Respiratory Journal.
HIV infection is an independent risk factor for predominantly obstructive lung function impairment; however, data on lung function impairment in HIV-associated TB are scarce, especially in paradoxical TB-IRIS and prophylactic prednisone. Researchers in South Africa sought to determine the prevalence of lung function abnormalities in patients with HIV-associated TB and CD4 counts ≤100 cells/µL and assessed the effect of a 28-day course of prophylactic prednisone and the development of paradoxical TB-IRIS on pulmonary impairment.
Of 153 enrolled participants, 71 (46%) developed TB-IRIS: 30 in the prednisone group and 41 in the placebo group. A total of 46 (30%) participants received open-label prednisone as treatment for TB-IRIS: 16 in the prednisone group and 30 in the placebo group. The researchers found that abnormal spirometry measurements were present in 66% of participants at week 0 and in 50% at week 28, with low forced vital capacity as the most frequent abnormality. Chest radiographs, on the other hand, showed few to no abnormalities in most patients.
Use of prednisone resulted in a 42-m greater 6-minute walk distance and a 4.9% higher percentage of predicted forced expiratory volume in 1 second at week 4, but these differences were no longer significant from week 12 on. Thus, TB-IRIS did not significantly impair lung function outcome.
“In conclusion, we found that lung function impairment is common in patients with HIV-associated TB,” stated the authors. However, “[o]verlap between the groups through the development of TB-IRIS and subsequent use of prednisone as treatment, limits our ability to make definitive conclusions.” Therefore, further studies are needed to better understand the pathogenesis of lung function impairment in HIV-associated TB.
Stek C, Allwood B, Du Bruyn E, et al. The effect of HIV-associated tuberculosis, tuberculosis-IRIS, and prednisone on lung function [published online December 20, 2019]. Eur Respir J. doi:10.1183/13993003.01692-2019