A Multicenter, 4-week Crossover (Total Duration 12 Weeks) to Determine the Impact of QVA149 on Nocturnal Oxygen Levels in Chronic Obstructive Pulmonary Disease (COPD)

Inclusion Criteria: * Clinical diagnosis of COPD (according to GOLD guidelines, updated 2014) with a post-bronchodilator FEV1/FVC \<0.70 * Patients with a post-bronchodilator FEV1 ≥30% and \<60% of the predicted normal value * Resting daytime oxygen saturation levels measured by pulse oximetry of ≤95% SpO2 * Smoking history of at least 10 pack years (Ten pack-years are defined as 20 cigarettes a day for 10 years, or 10 cigarettes a day for 20 years) Exclusion Criteria: * An exacerbation of COPD (treatment with oral or parenteral antibiotics and/or glucocorticosteroids and/or hospitalization related to COPD) within 4 weeks prior to screening or during the run-in period * Diagnosed asthma * Patients receiving regular long term oxygen therapy (LTOT) * Ongoing / planned rehabilitation during the study period * Three or more awakenings during the night leading to toilet visit or other reasons for exiting the bed during the last week prior to the screening visit due to non-COPD reasons Other protocol-defined inclusion/exclusion criteria may apply.