Influence of antimicrobial chemotherapy on spirometric parameters and pro-inflammatory indices in severe pulmonary tuberculosis

Patients who have completed a treatment for severe pulmonary tuberculosis (TB) are often left with severe respiratory disability. There have been few prospective studies assessing the effect of treatment on lung function in such patients. The influence of antimicrobial chemotherapy on lung function was investigated over a six month period in patients with newly diagnosed pulmonary TB to test the hypothesis that treatment improves lung function, as well as to identify factors that may influence lung function outcome. Seventy-six patients were recruited into the study, of whom 74 completed the treatment programme. Forty-two were current smokers and 13 seropositive for the human immunodeficiency virus. Improvement in lung function occurred in 54% of patients, but residual airflow limitation or a restrictive pattern was evident in 28% and 24% of patients, respectively. The extent of lung infiltration (radiographic score) both at the outset and after chemotherapy was significantly and negatively related to forced expiratory volume in one second (FEV1) (% pred) (r=-0.41, and r=.0.46, respectively). The post-treatment serum C-reactive protein and α1-protease inhibitor levels were negatively associated with FEV1 (% pred) (r=-0.30 and r=-0.35, respectively). These findings demonstrate that, while antimicrobial chemotherapy may lead to improved lung function in patients with pulmonary tuberculosis, a large proportion of patients has residual impairment. The most significant factor influencing posttreatment lung function status, as measured by forced expiratory volume in one second (% predicted), is the pretreatment and post-treatment radiographic score, which acts as a marker of the extent of pulmonary parenchymal involvement in tuberculosis.