Emergency department management of acute exacerbations of chronic obstructive pulmonary disease: factors predicting readmission

Figures & data

Table 1 Demographic data

	ED group (n=240)	Hospitalized group (n=271)	p-value
Age (mean, SD) years	61.57 (11.67)	70.84 (13.18)	<0.001***
Male	65.0%	64.6%	0.920
FEV1 (mean, SD)	54.54 (25.21)	45.65 (20.17)	0.001
BMI (mean, SD)	26.87 (8.08)	26.52 (7.65)	0.872
Current smoker	62.9%	36.5%	<0.001
Ever smoker	82.5%	70.1%	0.001
Pack-years (mean, SD)	43.51 (22.67)	39.52 (36.52)	0.013
Substance abuse	51.7%	22.1%	<0.001
Number of comorbidities (mean, SD)	5.28 (3.48)	3.74 (1.98)	<0.001
Mental health comorbidities	50.0%	29.9%	<0.001

Notes:

*** p<0.001. FEV₁ data available for 65% of ED group and 69% of hospitalized group; BMI available for 65% of ED group and 66% of hospitalized group; pack-years available for 60% of ED group and 71% of hospitalized group.

Abbreviations: ED, emergency department; FEV₁, forced expiratory volume in 1 second; BMI, body mass index; pack-years, 1 pack of 20 cigarettes for 1 year.

Table 2 Readmission rates between ED- and hospital-managed AECOPD

	ED group (n=240)		Hospitalized group (n=271)		p-value
	Mean	SD	Mean	SD
30-day ED readmissions	0.5417	1.1600	0.1956	0.6225	<0.001
90-day ED readmissions	1.2875	2.3207	0.5055	1.2409	<0.001
30-day hospital readmissions	0.1875	0.4600	0.2103	0.4831	0.578
90-day hospital readmissions	0.4250	0.8646	0.4871	0.8021	0.126
Time to readmission (days to first all-cause)	24.2101	22.1041	31.8450	27.8128	0.050

Notes: 30- and 90-day hospital admissions were not different between groups.

Abbreviations: ED, emergency department; AECOPD, acute exacerbations of chronic obstructive pulmonary disease.

Figure 1 Kaplan–Meier curves representing days until first readmission between the ED (emergency department group) and Ho (hospitalized group). The shaded areas represent the 95% confidence intervals. Readmissions in the ED group were significant sooner than in the hospitalized group (p=0.0063).

Table 3 Factors predicting all-cause readmission in the ED group

Predictor	Total 90-day all-cause (n=240)				Total 30-day all-cause (n=240)
	B	IRR-e^b	SE	p-value	B	IRR-e^b	SE	p-value
Intercept	0.0501	1.0514	0.3529	0.8870	0.4031	1.4964	0.4614	0.3824
Age	−0.0105	0.9895	0.0055	0.0562	−0.0223	0.9779	0.0079	0.005**
Female				NS				NS
Living with partner				NS	−0.9944	0.3699	0.3868	0.010*
Current smoker				NS				NS
Past smoker	−0.7279	0.4829	0.1657	<0.001***				NS
Substance abuse	0.4265	1.5318	0.1224	<0.001***				NS
Mental comorbidity	0.4285	1.5349	0.1162	<0.001***	0.5645	1.7585	0.1751	0.001**
Pulmonary comorbidity				NS	−0.3219	0.7248	0.1696	0.058
Cardiovascular comorbidity	0.4849	1.6239	0.1136	<0.001***	0.3530	1.4233	0.1740	0.043*
Number of comorbidities	0.0821	1.0856	0.0153	<0.001***	0.0518	1.0532	0.0248	0.036*

Notes:

* p<0.05,

** p<0.01,

*** p<0.001. The incidence rate ratio (IRR-e^b) shows the expected difference in the outcome (readmission rates) for one unit change in the predictor variable.

Abbreviations: ED, emergency department; NS, not significant; SE, standard error.

Table 4 Factors predicting COPD readmission in ED-managed patients

Predictor	Total 90-day COPD (n=157)				Total 30-day COPD (n=157)
	B	IRR-e^b	SE	p-value	B	IRR-e^b	SE	p-value
Intercept	1.9966	7.3638	0.6467	0.002	2.1739	8.7927	0.9224	0.018
Age	−0.0310	0.9694	0.0109	0.004	−0.0435	0.0957	0.0156	0.005
Female				NS				NS
Living with partner				NS	−1.1229	0.3253	0.7217	0.120
Current smoker				NS				NS
Past smoker	−0.8200	0.4404	0.2872	0.004				NS
SUD				NS				NS
Mental comorbidity				NS				NS
Pulmonary comorbidity	−0.3717	0.6896	0.2088	0.075				NS
Cardiovascular comorbidity	0.4961	1.6424	0.2097	0.018	0.5826	1.7907	0.2899	0.044
Number of comorbidities	0.1042	1.1098	0.0284	<0.001				NS
FEV1	−0.0212	0.9790	0.0046	<0.001	−0.0174	0.9828	0.0063	0.006

Notes: FEV₁: 157 patients had recent documented spirometry measurements available; IRR-e^b, expected difference in the outcome (readmission rates) for one unit change in the predictor variable.

Abbreviations: ED, emergency department; COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 second; NS, not significant; SE, standard error; SUD, substance abuse disorder.

Table 5 ED management (investigations and treatment) of AECOPD

Patient assessment – tests conducted	N	%
Chest imaging	223	92.92
• Chest X-ray	221	92.08
• Chest CT scan	10	4.17
Cardiovascular diagnostics (any of troponin, BNP, ECG, D-dimer)	134	55.83
• ECG, troponin, and/or pro-BNP	132	55.00
• D-Dimer (pulmonary embolism)	18	7.50
Infectious diagnostics (any of CBC, CRP, blood and sputum culture)	178	74.17
• CBC	177	73.75
• CRP	3	1.25
• Blood culture	14	5.83
• Sputum culture	12	5.00
Lung function	22	9.17
• ED peak flow or spirometry	19	7.92
• Blood gases	4	1.67
Patient treatment – medication provided	n	%
Appropriate treatment (bronchodilator, antibiotic, steroid)	118	49.17
• Prescribed bronchodilator	211	87.92
• Prescribed antibiotic	153	63.75
• Prescribed steroid	171	71.25
Follow-up – referrals given	n	%
Medical referral	164	68.33
• FP referral/notification	124	51.67
• Respiratory care referral (respirologist, pulmonary rehabilitation, puffer education)	54	22.50

Abbreviations: ED, emergency department; AECOPD, acute exacerbations of chronic obstructive pulmonary disease; CT, computed tomography; BNP, brain natriuretic protein; ECG, electrocardiogram; CBC, complete blood count; CRP, C-reactive protein; FP, family physician.