Hospital readmissions following initiation of nebulized arformoterol tartrate or nebulized short-acting beta-agonists among inpatients treated for COPD

Figures & data

Figure 1 Patient flow through the inclusion and exclusion criteria.

Abbreviations: COPD, chronic obstructive pulmonary disease; neb-SABA, nebulized short-acting β₂ agonist.

Table 1 Characteristics of arformoterol and nebulized SABA patients during initial hospitalization

Variable	Arformoterol (n=812)	Nebulized SABA (n=1,651)	P-value
	M ± SD or n (%)	M ± SD or n (%)
Age, years	68.6 ± 10.6	68.6 ± 10.6	0.877
Age group
40–54 years	86 (10.6%)	177 (10.7%)	0.922
55–64 years	186 (22.9%)	374 (22.7%)	0.888
65–74 years	290 (35.7%)	595 (36.0%)	0.875
75+ years	250 (30.8%)	505 (30.6%)	0.919
Female sex	463 (57.0%)	946 (57.3%)	0.895
Caucasian race	678 (83.5%)	1,166 (70.6%)	<0.001
Geographic location
Midwest	248 (30.5%)	278 (16.8%)	<0.001
South	477 (58.7%)	835 (50.6%)	<0.001
Northeast	57 (7.0%)	189 (11.4%)	<0.001
West	30 (3.7%)	349 (21.1%)	<0.001
Rural hospital	182 (22.4%)	284 (17.2%)	0.002
Emergency admission	692 (85.2%)	1,510 (91.5%)	<0.001
ICU care for at least one day	261 (32.1%)	304 (18.4%)	<0.001
APR-DRG severity of illness
Minor	68 (8.5%)	137 (8.3%)	0.867
Moderate	237 (29.2%)	483 (29.3%)	0.972
Major	345 (42.5%)	699 (42.3%)	0.944
Extreme	161 (19.8%)	332 (20.1%)	0.870
Therapy
Respiratory therapy	800 (98.5%)	1,601 (97.0%)	0.021
Oxygen saturation test	523 (64.4%)	930 (56.3%)	0.001
Oxygen therapy	633 (78.0%)	1,177 (71.3%)	<0.001
Non-β2 agonists
Anticholinergics	624 (76.8%)	1,236 (74.9%)	0.282
Corticosteroids	708 (87.2%)	1,273 (77.1%)	<0.001
Antibiotics	707 (87.1%)	1,470 (89.0%)	0.152
Other	4 (0.5%)	21 (1.3%)	0.070

Notes: Differences in mean age was evaluated using a t-test. Differences on the categorical variables were evaluated using chi-square tests.

Abbreviations: APR-DRG, 3M™ All Patient Refined™-Diagnosis Related Groups; M, mean; SABA, nebulized short-acting β₂ agonist; SD, standard deviation; ICU, intensive care unit.

Figure 2 Unadjusted all-cause 30-day readmission rates for arformoterol-treated and nebulized SABA-treated patients by APR-DRG severity.

Notes: Unadjusted comparisons within each APR-DRG severity class were completed using chi-square tests. In the multivariate logistic regression that adjusted for initial admission differences, the odds for readmission were 31% lower (odds ratio 0.69, 95% confidence interval 0.51–0.92) for patients treated with arformoterol than for patients treated only with neb-SABA.
Abbreviations: APR-DRG, 3M™ All Patient Refined™-Diagnosis Related Groups; neb-SABA, nebulized short-acting β₂ agonist.

Table 2 Logistic regression model

Variable	Estimate	OR	95% CI		P-value
Arformoterol	−0.377	0.686	0.511	0.920	0.012
Female sex	−0.077	0.858	0.663	1.11	0.244
Age group
40–50 years	−0.050	0.870	0.457	1.656	0.821
51–60 years	−0.039	0.879	0.617	1.252	0.800
Nonwhite race	0.044	1.092	0.814	1.465	0.557
Rural hospital	0.034	1.070	0.75	1.525	0.710
Teaching hospital	0.152	1.164	0.865	1.566	0.317
Total hospital beds, n	0.00017	1.000	0.999	1.001	0.641
Primary diagnosis of COPD	0.191	1.210	0.912	1.606	0.186
Emergency admission	0.058	1.123	0.827	1.526	0.457
Length of stay, days	0.016	1.016	0.999	1.033	0.065
APR-DRG severity of illness
Moderate	0.433	1.542	0.823	2.886	0.176
Major	0.637	1.890	1.023	3.491	0.042
Extreme	0.911	2.487	1.276	4.846	0.007
Oxygen therapy	−0.030	0.970	0.713	1.321	0.848
Respiratory therapy	−0.171	0.843	0.371	1.914	0.682
Anticholinergic use	−0.136	0.873	0.649	1.175	0.370
Corticosteroid use	0.251	1.286	0.905	1.826	0.160
Antibiotic use	0.109	1.115	0.794	1.564	0.530
Intercept	−2.907				<0.001

Abbreviations: APR-DRG, 3M™ All Patient Refined™-Diagnosis Related Groups; CI, confidence interval; OR, odds ratio; COPD, chronic obstructive pulmonary disease.