Factors Associated with Indacaterol Response in Tuberculosis-Destroyed Lung with Airflow Limitation

Pulmonary tuberculosis can result in anatomical sequelae, and cause airflow limitation. However, there are no treatment guidelines for patients with a tuberculosis-destroyed lung. Recently, indacaterol effectiveness in chronic obstructive pulmonary disease (COPD) patients with Tuberculosis history (INFINITY) study revealed indacaterol provided bronchodilation and symptom improvement in COPD patients with a tuberculosis-destroyed lung.

We conducted a post-hoc subgroup analysis of the randomized controlled trial, the INFINITY study, to determine factors associated with indacaterol response in a tuberculosis-destroyed lung with airflow limitation. Data from 68 patients treated with inhaled indacaterol, were extracted and analyzed. Factors associated with the response of forced expiratory volume in one second (FEV₁) to indacaterol treatment, were determined using linear regression analysis.

Of 62 patients included, 68% were male, and 52% had history of cigarette smoking. Patients revealed mean FEV₁ of 50.5% of predicted value with mean improvement of 81.3 mL in FEV₁ after indacaterol treatment for 8 weeks. Linear regression analysis revealed factors associated with response of FEV₁ to indacaterol included a short duration of smoking history, and high short-acting bronchodilator response. When patients with history of smoking were excluded, factors associated with response of FEV₁ to indacaterol included high short-acting bronchodilator response, and poor healthrelated quality of life score as measured by St. George's Respiratory Questionnaire for COPD.

In a tuberculosis-destroyed lung with airflow limitation, short-acting bronchodilator response and smoking history can play a critical role in predicting outcomes of indacaterol treatment.