In this multicentre double-blind , double-dummy , parallel-group study , @ patients ( age @ years or older , Global Initiative for Chronic Obstructive Lung Disease -LSB- GOLD -RSB- stages II-III , without exacerbations in the previous year ) were randomly assigned ( @:@ ; via automated , interactive response technology and stratified for smoking status ) to once-daily QVA@ @/@ g or twice-daily SFC @/@ g for @ weeks .