Pulmonary tuberculosis, impaired lung function, disability and quality of life in a high-burden setting

SETTING: Tuberculosis treatment clinic in Papua, Indonesia. OBJECTIVE: To document the impact of pulmonary tuberculosis (PTB) on lung function, exercise tolerance and quality of life (QOL). DESIGN: A prospective cohort study of 115 patients with smear-positive PTB followed for 6 months. Demographics, disease history, sputum microbiology, spirometry, 6-minute weight.walk distance (6MWWD) and QOL (modified St George's Respiratory Questionnaire) were measured at diagnosis and at 2 and 6 months. Analysis was restricted to the 69/115 (60%) subjects who attended all follow-up visits. RESULTS: Subjects who attended all visits were less likely than the full cohort to be of Papuan ethnicity (P < 0.05), were more likely to be cured (P < 0.001) and had better lung function at diagnosis (P < 0.05). Significant lung function impairment (forced expiratory volume in 1 second [FEV₁] <60% predicted) was found in 27/69 (39%) at diagnosis. Although this fell during treatment (P < 0.01), 17/69 (24.6%) had persisting significant lung function impairment at treatment completion. As lung function recovered, exercise tolerance (6MWWD) rose by 12.3% (P < 0.001) and QOL improved (P < 0.001). CONCLUSION: In a high-burden setting, PTB causes prolonged, significant impairment of lung function, exercise tolerance and QOL. Current measures of disease burden are likely to underestimate the true impact of disease. Earlier diagnosis and disease-modifying treatments may reduce the long-term impact of PTB.