Both doses of tiotropium resulted in significant improvement compared with placebo in the co-primary efficacy end points at the end of week 12 ( change from baseline in percent-predicted FEV1 AUC0-4h : 2.5 g : 2.94 % , 95 % confidence interval 1.19-4 .70 , p = 0.001 ; 5 g : 3.39 % , 95 % confidence interval 1.67-5 .12 , p = 0.0001 ; in percent-predicted trough FEV1 2.5 g : 2.24 % , p = 0.2 ; 5 g : 2.22 % , p = 0.02 ) .