Clinical characteristics of chronic bronchitic, emphysematous and ACOS phenotypes in COPD patients with frequent exacerbations

Figures & data

Table 1 Characteristics of all COPD patients with FE or iFE

Variables	Subjects with FE	Subjects with iFE	P-value
Total subjects (N)	60	82
Male (n)	47	62	0.841
Age (years)	72.1±8.24	66.72±10.97	0.001
History of COPD (years)	15.43±9.35	10.4±7.47	0.001
Smoking index (pack × years)	53.46±52.95	38.31±21.45	0.040
BMI (kg/m^2)	20.51±4.19	21.34±3.07	0.192
FEV1 (% predicted)	42.22±17.19	48.93±16.91	0.022
FEV1/FVC (%)	50.72±10.7	57.74±9.31	0.000
CAT score	29.53±3.9	23.77±6.26	0.000
mMRC	3.08±0.74	2.13±0.94	0.000
Emphysema score	2.3±1.43	2.02±1.52	0.275
Bronchial thickening score	1.25±0.68	0.95±0.7	0.012
Leukocyte (×10^9)	7.48±2.79	7.87±3.09	0.449
NLR	8.98±12.61	5.72±4.7	0.079
CRP (mg/L)	56.35±67.4	44.3±67.31	0.429
pH value	7.41±0.05	7.42±0.04	0.079
PaO2 (mmHg)	86.79±27.35	78.35±20.34	0.070
PaCO2 (mmHg)	45.69±12.4	41.19±8.88	0.040
Phenotypes of COPD			0.119
Chronic bronchitis (n)	30	27
Emphysema (n)	20	38
ACOS (n)	10	17
Medical history
Systemic hypertension (n)	16	13	0.141
Coronary heart disease (n)	7	2	0.036
Diabetes mellitus (n)	9	2	0.009

Notes: Data are presented as mean ± standard deviation, number (n), or percentage. P-value <0.05 was considered statistically significant: data shown in bold.

Abbreviations: ACOS, asthma–COPD overlap syndrome; BMI, body mass index; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; FE, frequent exacerbations; FEV₁, forced expiratory volume in 1 second; FEV₁/FVC, the ratio of FEV₁ and forced vital capacity; iFE, infrequent exacerbations; mMRC, modified British Medical Research Council breathlessness measurement; NLR, neutrophil lymphocyte ratio in whole blood; PaCO₂, arterial carbon dioxide pressure; PaO₂, arterial oxygen pressure.

Table 2 Characteristics of the chronic bronchitis phenotype in COPD patients with FE vs iFE

Variables	Subjects with FE	Subjects with iFE	P-value
Total subjects (N)	30	27
Male (n)	24	17	0.238
Age (years)	73±6.4	64.37±12.5	0.003
History of COPD (years)	14.17±9.5	10.44±8.45	0.124
Smoking (pack × years)	64.05±70.1	43.33±28.77	0.158
BMI (kg/m^2)	19.82±3.62	22.07±3.11	0.016
FEV1 (% predicted)	40±13.61	51.74±16.13	0.004
FEV1/FVC (%)	51.17±10.78	57.47±10.18	0.028
CAT score	29.4±3.94	23.41±6.98	0.000
mMRC	3.1±0.711	2.15±1.1	0.000
Emphysema score	1.97±1.56	0.63±1.15	0.001
Bronchial thickening score	1.43±0.68	1.19±0.4	0.095
Leukocytes (×10^9)	8.29±3.14	8.7±3.78	0.656
NLR	11.42±6.35	17.03±5.3	0.144
CRP (mg/L)	53.38±54.72	42.26±54.89	0.557
pH value	7.41±0.05	7.43±0.05	0.272
PaO2 (mmHg)	83.23±30.75	76.21±20.55	0.400
PaCO2 (mmHg)	49.42±13.21	37.54±4.77	0.000

Notes: Data are presented as mean ± standard deviation, number (n), or percentage. P-value <0.05 was considered statistically significant: data shown in bold.

Abbreviations: BMI, body mass index; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; FE, frequent exacerbations; FEV₁, forced expiratory volume in 1 second; FEV₁/FVC, the ratio of FEV₁ and forced vital capacity; iFE, infrequent exacerbations; mMRC, modified British Medical Research Council breathlessness measurement; NLR, neutrophil lymphocyte ratio in whole blood; PaCO₂, arterial carbon dioxide pressure; PaO₂, arterial oxygen pressure.

Table 3 Independent risk factors for FE in COPD patients with chronic bronchitis phenotype by multivariate analysis

Variables	OR	95% CI	P-value
FEV1	0.899	0.81–0.997	0.044
PaCO2	1.215	1.035–1.426	0.017

Note: P-value <0.05 was considered statistically significant.

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; FE, frequent exacerbations; FEV₁, forced expiratory volume in 1 second; OR, odds ratios; PaCO₂, arterial carbon dioxide pressure.

Table 4 Characteristics of emphysema phenotype in COPD patients with FE vs iFE

Variables	Subjects with FE	Subjects with iFE	P-value
Total subjects (N)	20	38
Male (n)	16	32	0.475
Age (years)	74±6.6	67.5±10.16	0.012
History of COPD (years)	19.85±9.05	10.66±7.28	0.000
Smoking (pack × years)	39.08±15.91	36.76±18.07	0.631
BMI (kg/m^2)	21.66±4.95	20.87±2.78	0.515
FEV1 (% predicted)	37.71±12.06	44.07±16.83	0.140
FEV1/FVC (%)	50.5±10.99	58.45±9.32	0.005
CAT score	31.1±1.71	23.87±5.98	0.000
mMRC	3.35±0.49	2.16±0.79	0.000
Emphysema score	2.75±1.12	2.87±0.88	0.658
Bronchial thickening score	1.43±0.68	1.19±0.4	0.151
Leukocytes (×10^9)	6.76±2.24	7.16±2.4	0.545
NLR	7.36±10.32	5.63±4.81	0.387
CRP (mg/L)	63.6±83.56	47.64±79.44	0.547
pH value	7.41±0.06	7.42±0.05	0.504
PaO2 (mmHg)	87.95±20.97	79.57±22.79	0.245
PaCO2 (mmHg)	43.87±10.86	44.69±10.71	0.812

Notes: Data are indicated as mean ± standard deviation, number (n), or percentage. P-value <0.05 was considered statistically significant: data shown in bold.

Abbreviations: BMI, body mass index; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; FE, frequent exacerbations; FEV₁, forced expiratory volume in 1 second; FEV₁/FVC, the ratio of FEV₁ and forced vital capacity; iFE, infrequent exacerbations; mMRC, modified British Medical Research Council breathlessness measurement; NLR, neutrophil lymphocyte ratio in whole blood; PaCO₂, arterial carbon dioxide pressure; PaO₂, arterial oxygen pressure.

Table 5 Independent risk factor for FE in COPD patients with emphysema phenotype by multivariate analysis

Variable	OR	95% CI	P-value
CAT	2.601	1.442–4.691	0.001

Note: P-value <0.05 was considered statistically significant.

Abbreviations: CAT, COPD assessment test; CI, confidence interval; COPD, chronic obstructive pulmonary disease; FE, frequent exacerbations; OR, odds ratio.

Table 6 Comparison of characteristics of ACOS phenotype in COPD patients with FE vs iFE

Variables	Subjects with FE	Subjects with iFE	P-value
Total subjects (N)	10	17
Male (n)	7	13	1.000
Age (years)	65.6±12.77	68.71±10.05	0.489
History of COPD (years)	10.4±5.72	9.76±6.57	0.802
Smoking (pack × years)	50.5±34.19	33.79±12.64	0.167
BMI (kg/m^2)	20.24±4.06	21.24±3.57	0.509
FEV1 (% predicted)	57.88±26.46	55.32±16.03	0.786
FEV1/FVC (%)	49.81±10.91	56.59±8.16	0.077
CAT score	26.8±5.47	24.12±6.0	0.258
mMRC	2.5±0.97	2.06±1.03	0.283
Emphysema score	2.4±1.43	2.35±1.62	0.940
Bronchial thickening score	0.7±0.67	0.59±0.62	0.665
Leukocyte (×10^9)	6.51±2.03	8.13±3.07	0.151
NLR	4.9±3.17	4.89±3.26	0.993
CRP (mg/L)	24.36±29.71	30.09±22.99	0.821
pH value	7.4±0.03	7.42±0.03	0.032
PaO2 (mmHg)	94.84±29.0	78.83±15.35	0.103
PaCO2 (mmHg)	38.39±9.53	39.14±6.65	0.829

Notes: Data are indicated as mean ± standard deviation, number (n), or percentage. P-value <0.05 was considered statistically significant: data shown in bold.

Abbreviations: ACOS, asthma–COPD overlap syndrome; BMI, body mass index; CAT, COPD assessment test; COPD, chronic obstructive pulmonary disease; CRP, C-reactive protein; FE, frequent exacerbations; FEV₁, forced expiratory volume in 1 second; FEV₁/FVC, the ratio of FEV₁ and forced vital capacity; iFE, infrequent exacerbations; mMRC, modified British Medical Research Council breathlessness measurement; NLR, neutrophil lymphocyte ratio in whole blood; PaCO₂, arterial carbon dioxide pressure; PaO₂, arterial oxygen pressure.