Figure 2.

Association between the presence of BDR and asthma control. Shown are the following: cutoff for poor asthma control (Asthma Control Test score < 20) (blue line); cutoff for BDR by spirometry or FOT (orange line); subjects with spirometric BDR (blue circles) or no spirometric BDR (red circles) in FEV₁ and/or FVC; region of concordance between BDR and poor asthma control (orange-shaded areas); Spearman’s correlation (r_s); change in parameter after bronchodilator administration (postbronchodilator minus prebronchodilator) (Δ). Spirometric BDR is defined as ≥ 200 mL and ≥ 12% improvement in FEV₁ and/or FVC. ACT = Asthma Control Test; AX = area under the reactance curve, between 5 Hz and resonant frequency; R5 = resistance at 5 Hz; X5 = reactance at 5 Hz. See Figure 1 legend for expansion of other abbreviations.