Effect of Indacaterol on Cough and Phlegm in Chronic Obstructive Pulmonary Disease Patients: A Meta-Analysis of Five Randomized Controlled Trials

We investigated the effects of indacaterol on cough and phlegm in patients with stable chronic obstructive pulmonary disease (COPD). We performed a meta-analysis with five randomized controlled trials (RCTs) of indacaterol in stable COPD patients. The symptom severity was defined using the St. George's Respiratory Questionnaire (SGRQ). We analyzed patients treated with 150 µg (n = 945) and 300 µg (n = 832) out of 3,325 patients who completed the SGRQ from five RCTs. After a 12-week treatment of 150 µg indacaterol, cough improvement was reported in 36.5% (316/866) of patients treated with indacaterol vs. 32.2% (259/804) patients treated with placebo (Relative Ratio [RR], 1.13; 95% confidence interval [CI], 0.99-1.29). Phlegm improvement was reported in 31.0% (247/798) of patients treated with indacaterol vs. 30.6% (225/736) of patients treated with placebo (RR, 1.01; 95% CI, 0.87-1.18). Dyspnea improvement was reported in 39.5% (324/820) of patients treated with indacaterol vs. 31.5% (237/753) patients treated with placebo (RR, 1.33; 95% CI, 1.03-1.71; P = 0.001, I(2) = 55.1%). Only dyspnea improvement was significant compared to placebo even at the 300 µg indacaterol dose. Compared to placebo, a 12-week treatment of the long-acting beta-agonist, indacaterol might not have a significant effect on cough or phlegm in stable COPD.