PD20 μg | Bronchodilator response# | Paediatric asthma quality-of-life score | Asthma severity score¶ | |
PEF % PB | 0.35; 0.04 (0.01–0.61) | -0.38; 0.02 (-0.64– -0.06) | -0.10; 0.58 (-0.43–0.26) | 0.08; 0.64 (-0.26–0.41) |
FEV1 % pred | 0.36; 0.03 (0.02–0.61) | -0.42; 0.01 (-0.66– -0.09) | 0.15; 0.39 (-0.20–0.47) | 0.06; 0.76 (-0.28–0.39) |
vPEF ampl/mean | -0.43; 0.009 (-0.67– -0.11) | 0.34; 0.04 (0.00–0.61) | -0.05; 0.79 (-0.39–0.31) | -0.15; 0.39 (-0.46–0.20) |
vFEV1 ampl/mean | -0.43; 0.008 (-0.67– -0.11) | 0.14; 0.41 (-0.20–0.46) | -0.15; 0.41 (-0.47–0.21) | -0.32; 0.06 (-0.59–0.02) |
Data are presented as Spearman’s rank correlation coefficient; p-value (95% confidence interval). PD20: dose of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1); %PB: percentage of personal best value; PEF: peak expiratory flow; % pred: % predicted; vPEF: variation in PEF; ampl/mean: size of day's range as a percentage of the day's mean; vFEV1: variation in FEV1. #: percentage of initial FEV1; ¶: %PB.