Comorbidity as a contributor to frequent severe acute exacerbation in COPD patients

Figures & data

Table 1 Baseline characteristics of 77 COPD patients with severe acute exacerbations

	Median (IQR, Q1–Q3) or number (%)
Age, years	73 (66–78)
Sex, male	67 (87.0)
Body mass index, kg/m^2	22.3 (20.6–25.2)
Smoking history
Current or former smoker	73 (94.8)
Comorbidities	61 (79.2)
Hypertension	35 (45.5)
Asthma	25 (32.5)
Malignancy	17 (22.1)
Diabetes mellitus	15 (19.5)
Ischemic heart disease	11 (14.3)
Cor pulmonale	8 (10.4)
Cerebrovascular disease	7 (9.1)
Congestive heart failure	6 (7.8)
Tuberculosis-destroyed lung	6 (7.8)
Chronic renal disease	5 (6.5)
Chronic liver disease	1 (1.3)
Pulmonary function tests
FEV1/FVC, %	45 (34–55)
FEV1, L	1.1 (0.8–1.5)
FEV1, % predicted	44 (32–57)
Laboratory findings
pHa in arterial blood	7.4 (7.4–7.5)
PaCO2,a mmHg	41 (36–47)
ESR,b mm/h	34 (14–51)
CRP, mg/dL	1.7 (0.4–6.2)
Procalcitonin,c ng/mL	0.1 (0.1–0.2)
Medical treatments
Home oxygen therapy	9 (11.7)
Long-term oral steroids	9 (11.7)
Inhalerd
None	9 (11.7)
ICS/LABA	53 (68.8)
LAMA	42 (54.5)
LABA	4 (5.2)
Others	6 (7.8)

Notes:

a Data for 69 patients were available.

b Data for 56 patients were available.

c Data for 47 patients were available.

d Reported inhaler use prior to first admission; some patients used more than one inhaler.

Abbreviations: CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; ICS, inhaled corticosteroid; IQR, interquartile range; LABA, long-acting β₂-agonist; LAMA, long acting muscarinic antagonist; PaCO₂, partial pressure of arterial CO₂.

Table 2 Treatment outcomes of 77 COPD patients with severe acute exacerbations

	Total (n=77)	Patients with or without early frequent severe AEs within 90 days			Patients with or without frequent severe AEs within 1 year
		Without severe AEs (n=58)	With severe AEs (n=19)	P-value	Without severe AEs (n=48)	With severe AEs (n=29)	P-value
Hospital stays, days	5 (2–9)	4 (2–8)	8 (3–11)	0.070	4 (2–8)	7 (3–10)	0.110
Duration of systemic steroid treatment during first severe	7 (5–10)	7 (5–10)	6 (5–10)	0.995	6 (5–9)	7 (5–12)	0.308
AE event, days
Total steroid dose prescribed between the first day of AE and OPD visit, mga	238 (188–376)	249 (188–360)	223 (188–400)	1.0	239 (188–338)	230 (188–429)	0.368
Deaths due to subsequent severe AEs	5 (6.5)	2 (3.4)	3 (15.8)	0.093	–	5 (17.2)	–

Notes: The data are presented as number (%) or as median and interquartile range.

a Steroid doses were calculated as equivalent doses of prednisolone.

Abbreviations: AE, acute exacerbation; OPD, outpatient department.

Table 3 Comparison of 77 COPD patients with or without frequent severe acute exacerbations during a 1-year follow-up period

	Patients without frequent severe AEs (n=48)	Patients with frequent severe AEs (n=29)	P-value
Age, years	74 (66–79)	71 (64–76)	0.377
Sex, male	42 (87.5)	25 (86.2)	1.0
Body mass index, kg/m^2	22.2 (20.5–25.1)	22.4 (20.8–25.4)	0.511
Smoking history
Current or former smoker	40 (83.3)	24 (82.8)	1.0
Comorbidities	35 (72.9)	26 (89.7)	0.079
Hypertension	20 (41.7)	15 (51.7)	0.390
Asthma	12 (25.0)	13 (44.8)	0.072
Malignancy	10 (20.8)	7 (24.1)	0.735
Diabetes mellitus	8 (16.7)	7 (24.1)	0.423
Ischemic heart disease	7 (14.6)	4 (13.8)	1.0
Cor pulmonale	4 (8.3)	4 (13.8)	0.466
Cerebrovascular disease	3 (6.2)	4 (13.8)	0.415
Congestive heart failure	3 (6.2)	3 (10.3)	0.667
Tuberculosis-destroyed lung	6 (12.5)	0 (0.0)	0.078
Chronic renal disease	2 (4.2)	3 (10.3)	0.359
Chronic liver disease	1 (2.1)	0 (0.0)	1.0
Pulmonary function tests
FEV1/FVC	45 (36–57)	41 (31–55)	0.254
FEV1, L	1.2 (0.9–1.6)	1.1 (0.7–1.3)	0.049
FEV1, % predicted	44 (33–63)	37 (27–55)	0.145
Laboratory findings
pH in arterial blooda	7.4 (7.4–7.5)	7.4 (7.4–7.5)	0.651
PaCO2,a mmHg	43 (37–47)	40 (35–50)	0.389
ESR,b mm/h	32 (14–51)	36 (22–55)	0.663
CRP, mg/dL	1.1 (0.3–4.9)	3.9 (0.5–10.6)	0.064
Procalcitonin,c ng/mL	0.1 (0.1–0.2)	0.2 (0.1–0.5)	0.083
Medical treatments
Home oxygen therapy	2 (4.2)	7 (24.1)	0.023
Long-term oral steroids	2 (4.2)	6 (20.7)	0.047
Use of ICS after severe AE	39 (81.3)	28 (96.6)	0.080

Notes: The data are presented as number (%) or as median and interquartile range.

a Data for 69 patients were available.

b Data for 56 patients were available.

c Data for 47 patients were available.

Abbreviations: AE, acute exacerbation; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; ICS, inhaled corticosteroids; PaCO₂, partial pressure of arterial CO₂.

Table 4 Comparison of 77 COPD patients with and without early frequent severe acute exacerbations (within 90 days)

	Patients without early frequent severe AEs (n=58)	Patients with early frequent severe AEs (n=19)	P-value
Age, years	74 (67–79)	68 (63–75)	0.135
Sex, male	50 (86.2)	17 (89.5)	1.0
Body mass index, kg/m^2	22.3 (20.3–25.4)	22.3 (21.4–24.8)	0.855
Smoking history
Current or former smoker	48 (82.8)	16 (84.2)	1.0
Comorbidities	43 (74.1)	18 (94.7)	0.099
Hypertension	26 (44.8)	9 (47.4)	0.847
Asthma	17 (29.3)	8 (42.1)	0.301
Malignancy	12 (20.7)	5 (26.3)	0.751
Diabetes mellitus	10 (17.2)	5 (26.3)	0.505
Ischemic heart disease	8 (13.8)	3 (15.8)	1.0
Cor pulmonale	5 (8.6)	3 (15.8)	0.400
Cerebrovascular disease	4 (6.9)	3 (15.8)	0.354
Congestive heart failure	3 (5.2)	3 (15.8)	0.156
Tuberculosis-destroyed lung	6 (10.3)	0 (0)	0.327
Chronic renal disease	4 (6.9)	1 (5.3)	1.0
Chronic liver disease	1 (1.7)	0 (0)	1.0
Pulmonary function tests
FEV1/FVC	45 (35–58)	41 (30–54)	0.135
FEV1, L	1.2 (0.9–1.6)	0.9 (0.6–1.2)	0.008
FEV1, % predicted	46 (33–62)	34 (20–48)	0.008
Laboratory findings
pH in arterial blooda	7.4 (7.4–7.5)	7.4 (7.3–7.5)	0.459
PaCO2,a mmHg	41 (36–46)	40 (35–67)	0.908
ESR,b mm/h	30 (15–50)	38 (20–64)	0.491
CRP, mg/dL	1.1 (0.3–5.5)	5.0 (0.4–9.5)	0.124
Procalcitonin,c ng/mL	0.1 (0.1–0.2)	0.2 (0.1–0.5)	0.146
Medical treatments
Home oxygen therapy	4 (6.9)	5 (26.3)	0.036
Long-term oral steroids	3 (5.2)	5 (26.3)	0.019
Use of ICS after severe AE	49 (84.5)	18 (94.7)	0.436

Notes: The data are presented as number (%) or as median and interquartile range.

a Data for 69 patients were available.

b Data for 56 patients were available.

c Data for 47 patients were available.

Abbreviations: AE, acute exacerbation; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; ICS, inhaled corticosteroid; PaCO₂, partial pressure of arterial CO₂.

Table 5 Multiple logistic regression analysis of clinical factors and comorbidities associated with frequent severe acute exacerbations during 1-year of follow-up and early frequent severe acute exacerbations during 90 days of follow-up

	Adjusted odds ratio	95% confidence interval	P-value
	Factors associated with frequent severe AEs during 1-year of follow-upa
Asthma	4.02	1.30–12.46	0.016
Home oxygen therapyb	9.39	1.60–55.30	0.013
CRP	1.09	1.01–1.19	0.036
	Factors associated with early frequent severe AEs during 90 days of follow-upa
FEV1, L	0.16	0.04–0.70	0.015

Notes:

a Adjusted for age, sex, asthma, ischemic heart disease, congestive heart failure, FEV₁ (L), CRP, home oxygen therapy, and long-term oral steroid.

b Unstable due to the fact that only two of nine patients who used home oxygen therapy did not develop AE.

Abbreviations: AE, acute exacerbation; CRP, C-reactive protein; FEV₁, forced expiratory volume in 1 second.