Table 2.

Patient characteristics of the two groups before pulmonary rehabilitation

	Time only-increased group (n=18)	Two factors-increased group (n=11)	P-value between groups
Age, years	69.7±7.9	71.6±7.7	0.357
BMI, kg⋅m−2	20.6±2.9	21.0±5.0	0.964
GOLD stage, I/II/III/IV	0/1/12/5	1/0/6/4	0.463
Pulmonary function
FEV1, L	0.93±0.32	0.94±0.50	0.406
%FEV1, % predicted	35.4±11.5	37.6±19.3	0.653
FEV1/FVC, %	39.7±9.5	44.8±10.9	0.291
VC, L	2.83±0.65	2.70±0.59	0.445
%VC, %	88.1±17.6	87.6±17.7	0.653
CPET with BGA, at peak exercise
${\dot{\mathrm{V}}\mathrm{O}}_2$, mL⋅min−1⋅kg−1	14.8±3.7	14.2±3.4	0.707
pH	7.351±0.040	7.344±0.052	0.702
PaO2, mmHg	63.3±13.1	63.6±11.4	0.964
PaCO2, mmHg	43.7±6.4	43.2±6.6	0.857
Plasma lactate, mg⋅dL−1	34.7±12.4	35.3±13.6	0.963

Notes: Data are presented as mean ± SD (range) unless otherwise stated. In the time only increased group, exercise time was increased, but the peak ${\dot{\mathrm{V}}\mathrm{O}}_2$ was economized after pulmonary rehabilitation; in the two factors increased group, both the exercise time and the peak ${\dot{\mathrm{V}}\mathrm{O}}_2$ were increased after pulmonary rehabilitation.

Abbreviations: BGA, blood gas analyses; BMI, body mass index; CPET, cardiopulmonary exercise testing; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; PaCO₂, arterial carbon dioxide tension; PaO₂, arterial oxygen tension; VC, vital capacity; ${\dot{\mathrm{V}}\mathrm{O}}_2$, oxygen uptake.