Risk factors for FEV₁ decline in mild COPD and high-risk populations

Figures & data

Figure 1 Flow diagram of the study.

Abbreviations: FEV₁, forced expiratory volume in the first second of expiration; FVC, forced vital capacity; LDCT, low-dose computed tomography.

Figure 2 The change in FEV₁ between baseline and the first-year follow-up.

Abbreviation: FEV₁, forced expiratory volume in the first second of expiration.

Table 1 Patient demographics and baseline characteristics

Demographic parameter	Mild COPD group (n=72)	High-risk group (n=225)	P-value
Mean age, years (SD)	57.23±7.56	61.74±8.52	<0.0001
Range	(48.00, 80.00)	(47.00, 77.00)
Male, n (%)	46 (63.89)	165 (73.33)	0.124
BMI, kg/m^2 (SD)	24.58±2.82	24.64±3.15	0.882
Mean cigarette smoking years (SD)	19.43 (20.95)	18.63 (19.10)	0.762
Occupational exposure, n (%) – including dust and harmful gas	2 (2.78)	16 (7.11)	0.180
Bioaerosol exposure, n (%)	0	1 (0.44)	0.571
Allergic rhinitis, n (%)	5 (6.94)	9 (4.00)	0.305
Family disease history, n (%)	12 (16.67)	25 (11.11)	0.214
Chronic bronchitis	6 (8.33)	11 (4.89)	0.274
Emphysema	0 (0.00)	11 (4.89)	0.056
COPD	0 (0.00)	6 (2.67)	0.162
Asthma	1 (1.39)	1 (0.44)	0.430
Bronchiectasis	0 (0.00)	0 (0.00)	–
Lung cancer	5 (6.94)	5 (2.22)	0.053
CAT score (SD)	5.21 (4.62)	4.2 (3.73)	0.118
>6	20 (27.78)	43 (19.11)	0.117
≤6	52 (72.22)	182 (80.89)
mMRC score (SD)	0.43 (0.67)	0.25 (0.50)	0.014
0	48 (66.67)	176 (78.22)	0.035
1	17 (23.61)	42 (18.67)
2–3	7 (9.72)	7 (3.11)
EI (%)	11.44±8.18 (n=47)	9.18±8.39 (n=59)	0.167
Lung function (SD)
FEV1 (L)	2.37 (0.53)	2.62 (0.55)	0.001
FEV1% predicted	91.41 (8.67)	87.48 (6.21)	<0.0001
FVC (L)	3.62 (0.80)	3.32 (0.64)	0.002
FVC% predicted	111.68 (11.12)	91.32 (7.6)	0.001
FEV1/FVC%	65.59 (3.64)	78.91 (7.12)	<0.0001

Abbreviations: BMI, body mass index; CAT, COPD Assessment Test; mMRC, modified British Medical Research Council; EI, Emphysema Index; FEV₁, forced expiratory volume in the first second of expiration; FVC, forced vital capacity; SD, standard deviation.

Table 2 The factors influencing FEV₁% predicted decline in the mild COPD group

Variables	P (univariate)	OR (95% CI; univariate)	P-value*	OR (95% CI)*
Age group 3-1	0.342	0.306 (0.029, 3.169)
Age group 3-2	0.619	0.802 (0.211, 3.043)
Gender 2-1	0.134	0.375 (0.104, 1.352)
BMI	0.130	1.196 (0.949, 1.508)
Exposure 2-1	0.536	1.594 (0.364, 6.979)
Family history 2-1	0.462	0.431 (0.046, 4.069)
CAT 2-1	0.055	3.714 (0.973, 14.177)	0.033	5.310 (1.141, 24.718)
mMRC 2-0	0.929	0.842 (0.128, 5.561)
mMRC 2-1	0.857	0.800 (0.102, 6.249)
Smoking years 2	0.318	0.983 (0.951, 1.016)
EI 2-1	0.035	4.140 (1.104, 15.521)	0.023	5.681 (1.274, 25.325)

Note:

* Multivariate logistic regression.

Abbreviations: FEV₁, forced expiratory volume in the first second of expiration; OR, odds ratio; CI, confidence interval; BMI, body mass index; CAT, COPD Assessment Test; mMRC, modified British Medical Research Council; EI, Emphysema Index.

Table 3 The factors influencing FEV₁% predicted decline in the high-risk group

Variables	P (univariate)	OR (95% CI; univariate)
Age group 3-1	0.621	0.241 (0.022, 2.583)
Age group 3-2	0.420	0.188 (0.018, 2.002)
Gender 2-1	0.838	1.268 (0.13, 12.378)
BMI	0.999	1.000 (0.770, 1.299)
Exposure 2-1	0.157	0.256 (0.039, 1.69)
Family history 2-1	0.975	–
CAT 2-1	0.772	0.714 (0.074, 6.944)
mMRC 2-0	0.958	–
mMRC 2-1	0.984	–
Smoking years 2	0.261	1.024 (0.983, 1.066)
EI 2-1	0.710	0.65 (0.067, 6.296)

Abbreviations: FEV₁, forced expiratory volume in the first second of expiration; OR, odds ratio; CI, confidence interval; BMI, body mass index; CAT, COPD Assessment Test; mMRC, modified British Medical Research Council; EI, Emphysema Index.

Table 4 Cytokine levels in the fast-decline and slow-decline groups

Cytokines (pg/mL)	Fast-decline group	Slow-decline group	F-value	P-value
Leptin	2.37 (0.53)	2.62 (0.55)	1.305	0.261
MMP-10	91.41 (8.67)	87.48 (6.21)	0.735	0.397
CCL-4	3.62 (0.80)	3.32 (0.64)	0.365	0.550
CCL-2	111.68 (11.12)	94.85 (46.50)	0.295	0.590
VEGF	65.59 (3.64)	78.91 (7.12)	0.450	0.507
IL-1	109.24 (24.98)	96.74 (21.59)	0.523	0.474
IL-8	67.89 (13.06)	88.26 (16.93)	1.402	0.793
IGF-1	145.61 (33.81)	114.32 (25.77)	0.070	0.793

Abbreviations: MMP-10, matrix metalloproteinase-10; CCL-4, carbon tetrachloride-4; CCL-2, carbon tetrachloride-2; VEGF, vascular endothelial growth factor; IL-1, interleukin-1; IL-8, interleukin-8; IGF-1, insulin-like growth factor 1.