Is a previous diagnosis of asthma a reliable criterion for asthma–COPD overlap syndrome in a patient with COPD?

Figures & data

Figure 1 Distribution of non-ACOS and ACOS patients.

Abbreviation: ACOS, asthma–COPD overlap syndrome.

Table 1 Baseline characteristics of patients with ACOS defined as COPD with a previous diagnosis of asthma before the age of 40 years versus non-ACOS patients

Variable	Non-ACOS (n=2,629)	ACOS (n=496)	Total (n=3,125)	P-value
Sex (men)	2,229 (84.8%)	346 (69.8%)	2,575 (82.4%)	<0.001
Age (years)	67.4 (0.2)	64.6 (0.4)	66.9 (0.2)	<0.001
BMI (kg/m^2)	27.7 (0.1)	28.3 (0.2)	27.8 (0.1)	0.003
Active smoker	601 (22.9%)	125 (25.2%)	726 (23.2%)	0.082
Pack-years	41.3 (0.5)	32.3 (1.2)	40.1 (0.5)	<0.001
Time walked per day, minutes	63.3 (2.1)	66.1 (2.12)	63.7 (2.0)	0.36
Spirometry (postbronchodilator)
FVC (L)	2.8 (0.02)	3.02 (0.04)	2.9 (0.02)	0.0001
FVC%	68.7 (0.4)	75.2 (0.9)	69.7 (0.4)	<0.001
FEV1 (L)	1.5 (0.01)	1.7 (0.03)	1.6 (0.01)	<0.001
FEV1%	51.9 (0.4)	59.4 (1.0)	53.0 (0.3)	<0.001
FEV1/FVC	53.4 (0.2)	55.3 (0.6)	53.7 (0.2)	<0.001
Symptoms
mMRC, mean (SD)	1.7 (0.02)	1.7 (0.04)	1.7 (0.02)	0.31
Chronic cough	1,939 (73.8%)	389 (78.4%)	2,328 (74.5%)	0.07
Daily expectoration	1,650 (62.8%)	325 (65.5%)	1,975 (63.2%)	0.38
BODEx index	2.9 (0.04)	2.5 (0.08)	2.9 (0.04)	<0.001
Charlson Comorbidity Index	1.4 (0.06)	1.4 (0.07)	1.4 (0.07)	0.82
Positive bronchodilator test (FEV1 >12%, >200 mL.)	99 (3.9%)	56 (11.3%)	155 (5.0%)	<0.001
Very positive bronchodilator test* (FEV >15%, >400 mL)	231 (8.9%)	140 (22.2%)	371 (11.9%)	<0.001
% blood eosinophilic count (mean, SEM)	2.9 (0.2)	4.8 (0.4)	3.4 (0.2)	<0.001
Clinical/radiologic signs of emphysema	1,035 (39.4%)	161 (32.5%)	1,196 (38.3%)	0.007
Number of exacerbations in the previous 12 months	1.8 (0.03)	2.0 (0.07)	1.8 (0.03)	0.0006
Hospital admissions in the previous 2 years	1.0 (0.03)	1.2 (0.08)	1.0 (0.03)	0.03

Notes: Data are shown as the mean (SEM) unless otherwise specified.

* Very positive bronchodilator test recorded at any time during the previous year, while positive bronchodilator test refers to the inclusion spirometry.

Abbreviations: ACOS, asthma–COPD overlap syndrome; n, number; BMI, body mass index; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; mMRC, modified Medical Research Council Dyspnea Scale; SD, standard deviation; BODEx, Body Mass Index, Airflow Obstruction, Dyspnea and Exacerbations; SEM, standard error of the mean.

Table 2 Severity of COPD, quality of life, anxiety, and depression in patients with ACOS defined as COPD with a previous diagnosis of asthma before the age of 40 years versus non-ACOS patients

Variable	Non-ACOS (n=2,629)	ACOS (n=496)	Total (n=3,125)	P-value
COPDSS	10.4 (0.1)	10.3 (0.2)	10.4 (0.1)	0.66
CAT	19.2 (0.2)	19.6 (0.4)	19.3 (0.1)	0.43
EQ-5D index	0.65 (0.01)	0.62 (0.01)	0.65 (0.01)	0.03
EQ-5D VAS	57.7 (0.4)	57.4 (0.8)	57.6 (0.3)	0.79
Anxiety (HADS)	7.7 (0.1)	8.7 (0.2)	7.8 (0.1)	<0.001
Probable anxiety (≥8 points)	27.6%	34.9%	28.8%	0.0011
Depression (HADS)	7.7 (0.1)	8.2 (0.2)	7.8 (0.1)	0.007
Probable depression (≥8 points)	29.2%	36.6%	30.4%	0.0011

Note: Data are shown as the mean (SEM) unless otherwise specified.

Abbreviations: ACOS, asthma–COPD overlap syndrome; n, number; COPDSS, COPD Severity Score; CAT, COPD Assessment Test; EQ-5D, EuroQoL-5 dimensions; VAS, visual analog scale; HADS, Hospital Anxiety and Depression Scale; SEM, standard error of the mean.

Table 3 Baseline characteristics of patients with an ACOS 1 phenotype defined as patients with COPD fulfilling the Spanish consensus criteria for ACOS, and ACOS 2 defined as COPD with only a previous diagnosis of asthma before the age of 40 years

Variable	ACOS 1 (n=158)	ACOS 2 (n=338)	P-value
Sex (men)	113 (71.5%)	233 (68.9%)	0.56
Age (years)	63.4 (0.7)	65.1 (0.5)	0.06
BMI (kg/m^2)	28.7 (0.3)	28.2 (0.2)	0.22
Active smoker	42 (26.6%)	83 (26.9%)	0.59
Pack-years	33.4 (1.9)	31.9 (1.4)	0.006
Time walked per day, minutes	65.7 (2.1)	66.3 (2.0)	0.62
Spirometry, postbronchodilator
FVC (L)	3.1 (0.07)	3.0 (0.05)	0.53
FVC%	76.3 (1.6)	74.8 (1.1)	0.43
FEV1 (L)	1.8 (0.05)	1.7 (0.04)	0.02
FEV1%	63.0 (1.6)	57.8 (1.2)	0.012
FEV1/FVC	56.1 (1.1)	54.9 (0.6)	0.09
Symptoms
mMRC, mean (SD)	1.7 (0.07)	1.6 (0.05)	0.07
Chronic cough	130 (82.3%)	259 (76.6%)	0.33
Daily expectoration	113 (71.5%)	212 (62.7%)	0.08
BODEx index, mean (SD)	2.5 (0.1)	2.5 (0.1)	0.62
Charlson Comorbidity Index	1.6 (0.07)	1.3 (0.06)	0.005
% blood eosinophilic count (mean, SD)	4.9 (0.5)	4.7 (0.6)	0.14
Number of exacerbations in the previous 12 months	2.3 (0.1)	1.9 (0.1)	0.006
Hospital admissions in the previous 2 years	1.2 (0.1)	1.1 (0.1)	0.39

Note: Data are shown as the mean (SEM) unless otherwise specified.

Abbreviations: ACOS, asthma–COPD overlap syndrome; n, number; BMI, body mass index; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; mMRC, Modified Medical Research Council Dyspnea Scale; SD, standard deviation; BODEx, Body Mass Index, Airflow Obstruction, Dyspnea and Exacerbations; SEM, standard error of the mean.

Table 4 Severity of COPD, quality of life, anxiety, and depression in the ACOS 1 group, defined as patients with COPD fulfilling the Spanish consensus criteria for ACOS, and the ACOS 2 group, defined as COPD with only a previous diagnosis of asthma before the age of 40 years

Variable	ACOS 1 (n=158)	ACOS 2 (n=338)	P-value
COPDSS	9.7 (0.4)	10.5 (0.3)	0.07
CAT	19.6 (0.6)	19.5 (0.4)	0.89
EQ-5D index	0.61 (0.03)	0.62 (0.02)	0.71
EQ-5D VAS	56.0 (1.4)	57.7 (1.0)	0.33
HADS	17.07 (0.7)	16.8 (0.5)	0.83
Anxiety (HADS)	8.7 (0.4)	8.7 (0.2)	0.90
Probable anxiety (≥8 points)	30.9%	34.5%	0.46
Depression (HADS)	8.4 (0.4)	8.2 (0.3)	0.68
Probable depression (≥8 points)	37.3%	36.0%	0.79

Notes: P-values for comparisons have been calculated using linear regression models and logistic regression models. The variables FEV₁ and number of exacerbations have been included for adjustment. Data are shown as the mean (SEM) unless otherwise specified. P-values were obtained by linear regression models and logistic regression models adjusted by FEV₁ (%) and number of exacerbations in the previous year.

Abbreviations: ACOS, asthma–COPD overlap syndrome; n, number; COPDSS, COPD Severity Score; CAT, COPD Assessment Test; EQ-5D, EuroQoL-5 dimensions; VAS, visual analog scale; HADS, Hospital Anxiety and Depression Scale; SEM, standard error of the mean.