Effects of inhaler therapy on mortality in patients with tuberculous destroyed lung and airflow limitation

Purpose: Although patients with tuberculous destroyed lung (TDL) receive long-acting muscarinic antagonist (LAMA) inhaler therapy, its effectiveness is not clear. This study evaluated the effect of LAMA inhaler therapy on mortality in patients with TDL and airflow limitation. Patients and methods: A retrospective cohort of 683 patients with TDL and airflow limitation was analyzed in this study. The mortality was compared between 177 patients treated with LAMA inhalers >360 days (LAMA group) and 506 patients not treated with LAMA inhalers or treated with LAMA inhalers for <360 days (non-LAMA group). Risk factors for mortality were analyzed with Cox proportional hazards models and survival analysis was performed after propensity score matching. Results: Patients in the LAMA group appeared to have worse baseline characteristics, older mean age, lower lung function, higher X-ray severity, and were more likely to receive long-term oxygen therapy than those in the non-LAMA group. On multivariate analysis, LAMA inhaler usage was independently associated with lower risk of mortality (HR, 0.405; P=0.006) after adjusting age, gender, body mass index, smoking history, Charlson Comorbidity Index, lung function, X-ray severity, and long-term oxygen therapy. After propensity score matching to adjust for the above unbalanced baseline characteristics, patients in the LAMA group tended to have a better prognosis than those in the non-LAMA group (121 patients in each group, 5-year mortality rate: 2.5% vs 9.1%, P=0.057). If we performed the same analysis of propensity score matching even after excluding patients with corticosteroids/long-acting beta-2 agonist (ICS/ LABA) usage, patients in the LAMA group had a better prognosis than those in the non-LAMA group (64 patients in each group, 5-year mortality rate: 3.1% vs 14.1%, P=0.039). Conclusion: LAMA inhaler treatment might reduce mortality in patients with TDL and airflow limitation.