. 2016 Aug 1;11:1745–1756. doi: 10.2147/COPD.S111508

Table 1.

Characteristics of the patients with and without COPD

Characteristics	Non-COPD n=87				COPD n=395				P-value
Characteristics	N	%	Mean	SD	N	%	Mean	SD	P-value
Never smokers	59	67.8%			82	20.8%			<0.0001
Index patient	38	43.7%			353	89.4%			<0.0001
Female	56	64.4%			153	38.7%			<0.0001
Age	87		44.8	13.2	395		52.9	9.3	<0.0001
FEV₁ % predicted	87		113.4	15.7	395		53.1	21.9	<0.0001
FVC % predicted	87		115.5	16.6	395		109.4	22.4	0.002
FEV₁/FVC	87		82.9	7.2	395		39.0	12.7	<0.0001
TLco % predicted	47		87.1	21.6	247		61.4	18.1	<0.0001
Kco % predicted	87		89.4	18.4	394		62.8	18.0	<0.0001
RV % predicted	87		88.8	21.4	385		128.1	39.3	<0.0001
TLC % predicted	86		106.8	13.6	385		117.1	15.2	<0.0001
RV/TLC	86		27.4	8.6	385		36.5	8.7	<0.0001
FEV₁ % slope per year	87		−0.12	2.3	395		−1.14	1.8	<0.0001
Kco % slope per year	87		−1.06	2.1	377		−1.41	2.0	0.145
Distribution within FEV₁ decline groups
FEV₁ group 1	50	57.5%			93	23.5%			<0.0001
FEV₁ group 2	5	5.7%			42	10.6%
FEV₁ group 3	10	11.5%			59	14.9%
FEV₁ group 4	22	25.3%			201	50.9%
Distribution within Kco decline groups
Kco group 1	25	28.7%			72	19.1%			0.259
Kco group 2	6	6.9%			30	8.0%
Kco group 3	13	14.9%			60	15.9%
Kco group 4	43	49.4%			215	57.0%

Notes: TLco is overall gas transfer; Kco is gas transfer corrected for alveolar ventilation. % values indicate the proportion of each group with individual categorical characteristics. Significant P-values are given in bold.

Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁, forced expired volume in 1 second; FVC, forced vital capacity; SD, standard deviation; RV, residual volume; TLC, total lung capacity