At week 12 , the estimated least squares mean trough FEV1 difference between the groups was -0.011 L ( least squares mean with indacaterol [ n = 1450 ] 1.134 L [ SE 0.008 ] vs tiotropium [ n = 1467 ] 1.145 L [ 0.008 ] ; one-sided 97.5 % CI lower limit -0.026 L ; p < 0.0001 ) .