Fig. 1From: The Tiotropium Safety and Performance in Respimat® (TIOSPIR®) Trial: Spirometry OutcomesTrough forced expiratory volume in 1 second (FEV1) over time (a), and difference versus HandiHaler® 18 μg (b) [7]. Noninferiority was evaluated for treatment main effects using a noninferiority δ of 50 mL. Abbreviations: FEV1 = forced expiratory volume in 1 secondBack to article page