Table 3.

Characteristics of post-bronchodilator response in subgroups stratified by level of lung function impairment

Group	No.	Age (years, M [Q1, Q3])	ΔFEV1% init≥12% & ΔFEV1<200 mL (n)	Become positive with ΔFVC response (n)	Become positive with ΔFEV3 response (n)
A	2985	70 (65, 75)	2	2	69
B	1129	71 (66, 77)	14	9	50
C	1066	72 (67, 76)	28	18	63
D	837	73 (66, 77)	63	34	79
E	1183	73 (68, 77)	213	129	196
F	545	71 (66, 76)	176	122	136

Notes: ∆= change; % init, percentage of the initial value; % pred, percentage of the predicted value; Group A: FEV₁≥80% pred; Group B: 70% pred≤FEV₁<80% pred; Group C: 60% pred≤FEV₁<70% pred; Group D: 50% pred≤FEV₁<60% pred; Group E: 35% pred≤FEV₁<50% pred; Group F: FEV₁<35% pred.