Discriminative aspects of two generic and two asthma-specific instruments: relation with symptoms, bronchodilator use and lung function in patients with mild asthma

The objective of this study was to compare the two most frequently used asthma-specific quality of life (QOL) questionnaires and two generic QOL questionnaires with clinical data in order to establish their ability to discriminate in asthma severity, also referred to as cross-sectional construct validity. We conducted a multicentre, randomized, placebo-controlled study investigating the long-term effects of the long-acting ß2-agonist formoterol …