Figure 1.

(A) Absolute and (B) relative median changes per subject in lung clearance index (LCI) in preschool children treated with ivacaftor. Absolute LCI significantly improved 1 month after the first dose of ivacaftor (median [interquartile range (IQR)] LCI at 1 mo, 7.1 [6.6 to 8.5]; P = 0.02). The improvement in LCI was maintained 6 months after the first dose (median [IQR] LCI, 7.5 [7.3 to 7.6]; P = 0.03). Similarly, relative LCI significantly improved from baseline at both 1 month (median [IQR] change in LCI from baseline, −23.6% [−34.2 to −20.2]; P < 0.001) and 6 months after treatment (median [IQR] change in LCI from baseline, −24.6 [−31.4 to −20.4]; P < 0.001). The dotted lines represent an upper limit of normal of 8 in A and a change of 0% in B.