Vital capacity and COPD: the Swedish CArdioPulmonary bioImage Study (SCAPIS)

Figures & data

Table 1 Prevalence (%) of COPD according to different spirometric definitions in pilot SCAPIS according to sex and smoking habits

Investigated groups	All n=1,050			Never-smokers n=448		Ex-smokers n=415		Current smokers n=187
	All n=1,050	M n=525	F n=525	M n=217	F n=231	M n=220	F n=195	M n=88	F n=99
Non-COPD	83.1% n=873	80.6% n=423	85.7% n=450	88.5% n=192	92.6% n=214	79.6% n=175	82.1% n=160	63.6% n=56	76.8% n=76
GOLDCOPDFVC	10.0%a n=105	11.4%a n=60	8.6%a n=45	4.6%a n=10	4.8% n=11	10.9% n=24	9.7%a n=19	29.6%b,c n=26	15.2%a,b n=15
GOLDCOPDVC	16.4% n=173	19.0% n=100	13.9% n=73	10.6% n=23	6.9% n=16	20.5% n=45	17.4% n=34	36.4%b,c n=32	23.2%b n=23
GOLDCOPDVC>FVC	6.5% n=68	7.6% n=40	5.3% n=28	6.0% n=13	2.2% n=5	9.6% n=21	7.7% n=15	6.8% n=6	8.1% n=8
LLNCOPDFVC	9.5% n=100	10.8% n=57	8.2% n=43	5.1% n=11	3.9% n=9	10.4% n=23	9.2% n=18	26.1%b n=23	16.2%b n=16
LLNCOPDVC	15.6% n=164	18.0% n=95	13.1% n=69	11.1% n=24	6.1% n=14	17.7% n=39	16.9% n=33	36.4%b,c n=32	22.2%b n=22

Notes:

a P<0.05, GOLDCOPD_FVC vs GOLDCOPD_VC;

b P<0.05, current smokers vs never-smokers;

c P<0.05, males vs females. GOLDCOPD_FVC was defined as the ratio of FEV₁/FVC <0.7 using FEV₁ and FVC. GOLDCOPD_VC was defined as the ratio of FEV₁/VC <0.7 using VC defined as the highest value of FVC or SVC. GOLDCOPD_VC>FVC comprised subjects with GOLDCOPD_VC, but not with GOLDCOPD_FVC. LLNCOPD_FVC was defined as the ratio FEV₁/FVC below the LLN using FVC. LLNCOPD_VC was defined as the ratio of FEV₁/VC below the LLN using VC defined as the highest value of FVC or SVC.

Abbreviations: COPD, chronic obstructive pulmonary disease; F, female; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; LLN, lower limit of normal; M, male; SCAPIS, Swedish CArdioPulmonary bioImage Study; VC, vital capacity.

Table 2 Age, anthropometric data, hemoglobin, high specific CRP, and lung function values in 1,050 subjects in pilotSCAPIS according to different spirometric definitions of COPD

Characteristics	All (n=1,050)	Non-COPD (n=873)	GOLDCOPDFVC (n=105)	GOLDCOPDVC (n=173)	GOLDCOPDVC>FVC (n=68)
Age (years)	57.3 (0.14)	57.1 (0.15)	58.7 (0.41)a	58.4 (0.34)a	57.9 (0.58)
Males	50.0% (n=525)	48.5% (n=423)	57.1% (n=60)	57.8%a (n=100)	58.8% (n=40)
High SES (%)	37.4%	38.8%	24.8%a	29.5%a	36.8%
Weight (kg)	80.5 (0.48)	80.0 (0.51)	81.5 (1.70)	83.0 (1.34)	85.4 (2.16)a
Height (cm)	171.6 (0.30)	171.3 (0.32)	172.9 (0.96)	173.2 (0.78)	173.7 (1.31)
BMI (kg/m^2)	27.3 (0.14)	27.2 (0.15)	27.2 (0.50)	27.6 (0.38)	28.2 (0.57)
Hb (g/L)	140.6 (0.38)	140.2 (0.42)	142.3 (1.20)	142.7 (0.92)	143.3 (1.45)a
CRP	2.3 (0.11)	2.2 (0.11)	3.2 (0.44)a	2.8 (0.34)a	2.2 (0.52)b
FEV1 (% pred)	99.9 (0.71)	102.3 (0.75)	83.1 (2.17)a	87.6 (1.79)a	94.5 (2.91)a
FVC (% pred)	100.5 (0.73)	100.3 (0.79)	100.6 (2.38)	101.0 (1.94)	101.6 (3.33)
FEV1/FVC	0.78 (0.0020)	0.80 (0.0015)	0.64 (0.0059)a	0.68 (0.0049)a	0.73 (0.0027)a,b
KCO (% pred)	93.8 (1.16)	94.3 (1.26)	91.0 (5.0)	92.7 (1.46)	91.3 (2.50)
TLCO (% pred)	100.0 (0.47)	96.6 (0.48)	89.5 (2.03)a	84.8 (1.9)a	97.5 (1.86)
TLCO-Hb adjusted (% pred)	99.4 (0.36)	99.7 (0.35)	96.5 (1.72)	98.0 (1.23)	100.3 (1.85)
TLC (% pred)	110.3 (0.57)	109.2 (0.60)	116.5 (2.22)a	116.3 (1.65)a	116.0 (2.44)a
RV (% pred)	104.4 (0.69)	102.0 (0.71)	118.4 (2.70)a	117.1 (1.94)a	115.2 (2.73)a

Notes: Values are mean ± (SE), unless otherwise specified.

a P<0.05, compared with non-COPD subjects.

b P<0.05, GOLDCOPD_VC>FVC vs GOLDCOPD_FVC. GOLDCOPD_FVC was defined as the ratio of FEV₁/FVC <0.7 using FEV₁ and FVC. GOLDCOPD_VC was defined as the ratio of FEV₁/VC <0.7 using VC defined as the highest value of FVC or SVC. GOLDCOPD_VC>FVC comprised subjects with GOLDCOPD_VC, but not with GOLDCOPD_FVC.

Abbreviations: BMI, body mass index; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; K_CO, transfer coefficient; TL_CO, gas diffusing capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; pred, predicted; Hb, hemoglobin; RV, residual volume; SCAPIS, Swedish CArdioPulmonary bioImage Study; SE, standard error; SES, socioeconomic status; TLC, total lung capacity; VC, vital capacity.

Table 3 Cross-tabulation of different spirometric definitions of COPD in pilotSCAPIS

COPD definitions	GOLDCOPDFVC	GOLDCOPDVC	LLNCOPDFVC
All	105	173	100
GOLDCOPDFVC	–	105 (60.7%)	92 (92.0%)
GOLDCOPDVC	105 (100.0%)	–	100 (100.0%)
LLNCOPDFVC	92 (87.6%)	100 (57.8%)	–

Abbreviations: COPD, chronic obstructive pulmonary disease; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; LLN, lower limit of normal; SCAPIS, Swedish CArdioPulmonary bioImage Study; VC, vital capacity.

Table 4 Prevalence (%) of COPD according to different stages according to the GOLD criteria in pilotSCAPIS

COPD definitions	All, n	Stage 1, n (%)	Stage 2, n (%)	Stage 3, n (%)	Stage 4, n (%)
GOLDCOPDFVC	105	53 (50.5)	47 (44.8)	5 (4.8)	0
GOLDCOPDVC	173	98 (56.6)	69 (39.9)	6 (3.5)	0
GOLDCOPDVC>FVC	68	45 (66.2)	22 (32.3)	1 (1.5)	0

Abbreviations: COPD, chronic obstructive pulmonary disease; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; SCAPIS, Swedish CArdioPulmonary bioImage Study; VC, vital capacity.

Table 5 Comparison of the prevalence of dyspnea (according to MRC dyspnea scale), chronic bronchitis, asthma, and wheeze in relation to different spirometric definitions of COPD

Covariates (questionnaire-based)	All n=1,052	Non-COPD n=873	GOLD COPDFVC n=105	GOLD COPDVC n=173	GOLD COPDVC>FVC (n=68)
MRC grade 1	4.4% n=45	3.6% n=31	11.1%a n=11	8.6%a n=14	4.7% n=3
MRC > grade 1	6.0% n=60	4.6% n=40	15.1%a n=15	12.2%a n=20	7.9% n=5
Chronic bronchitis	7.2% (n=76)	6.5% (n=57)	12.4%a n=13	10.4% n=18	7.3% n=5
Physician-diagnosed asthma	9.2% n=97	7.3% (n=64)	21.9%a n=23	18.5%a n=32	13.2% n=9
Wheeze	8.6% n=90	5.6% (n=49)	28.6%a n=30	23.1%a n=40	14.7% n=10

Note:

a P<0.05, compared with non-COPD subjects.

Abbreviations: COPD, chronic obstructive pulmonary disease; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; MRC, Medical Research Council; VC, vital capacity.

Table 6 Logistic regression models of GOLDCOPD_VC>FVC vs non-COPD as the dependent variable

Independent variables	Odds ratio	95% confidence interval	P-value
Sexa	1.6	0.9–2.7	0.11
Age (years)	1.08	1.01–1.15	0.03
Current smokersb	1.6	0.7–3.3	0.23
Never-smokersb	0.6	0.3–1.2	0.16
Physician-diagnosed asthmab	1.7	0.8–3.8	0.19
Wheezeb	2.3	1.05–4.9	0.04
FEV1 (% predicted)	0.82	0.78–0.86	<0.001
FVC (% predicted)	1.19	1.14–1.24	<0.001
RV (% predicted)	1.02	1.01–1.04	<0.001

Notes:

a Males =1, females =0.

b 1= Yes, 0= No.

Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; RV, residual volume; VC, vital capacity.