Acute Exacerbations of COPD in the United States: Inpatient Burden and Predictors of Costs and Mortality

Figures & data

Table 1.  Hospitalization costs due to AECOPD

		Aggregate costs		Mean (±SD) costs		Median costs
	N (weighted)	2006	2010^e	2006	2010^e	2006	2010^e
AECOPD (overall)^a	1,254,703	$11.98 billion	$14.05 billion	$9545 (±12 700)	$11,195 (±14895)	$6062	$7110
Principal diagnosis for AECOPD^b	421,251	$2.96 billion	$3.47 billion	$7015 (±8289)	$8228 (±9722)	$4983	$5844
AECOPD excluding mechanical ventilation^c	1,107,220	$8.38 billion	$9.83 billion	$7569 (±7434)	$8877 (±8719)	$5583	$6548
AECOPD with mechanical ventilation^d	147,473	$3.59 billion	$4.22 billion	24,374 (±26 608)	28,588 (±31 208)	$16,098	$18,881

^aInclusion criteria: 1) ICD-9 code for obstructive chronic bronchitis (491.2x); or 2) presence of any other ICD-9 code for COPD (490–492, 494–496) with a concurrent diagnosis for pneumonia (481–486) or, a procedure code for mechanical ventilation (93.90, 96.70, 96.71, 96.72).

^bInclusion criteria: ICD-9 code 491.21 indicating an AECOPD in the principal diagnosis position.

^cSame as a) above excluding procedure codes for mechanical ventilation (93.90, 96.70, 96.71, 96.72).

^dHospitalizations with a procedure codes for mechanical ventilation (93.90, 96.70, 96.71, 96.72) from overall sample initially identified as described in a) above.

^eInflation adjusted to 2010 US$.

Table 2.  Patient characteristics and primary payer of acute exacerbations of chronic obstructive pulmonary disease discharges in 2006^a

Patient characteristic	Hospital discharges N = 1,254,703 (weighted)
Mean age (±SD) (years)	70.6 (±11.9)
Age
≤61	22.6
>61–71	26.8
>71–79	25.3
≥80	25.3
Missing	–
Sex
Female	52.8
Male	47.2
Missing	<0.1
Median household income by ZIP code
$0–24,999	33.7
$25,000–34,999	27.2
$35,000–44,999	21.5
$45,000+	15.1
Missing	2.4
Race^b
White	59.4
Black	5.9
Hispanic	3.7
Asian/Pacific islander	0.6
Native American	0.5
Other	1.0
Missing	28.9
Primary payer
Medicare	74.8
Medicaid	7.9
Private insurance	12.6
Self-pay	2.3
No charge	0.3
Other	1.9
Missing	0.2
Mean Deyo-modified Charlson co-morbidity index (±SD)	2.3 (±1.6)
Missing	–

^aAll values are given as% of all hospital discharges, unless otherwise indicated.

^bWhen missing values are excluded the percentage in each race category are as follows: White (83.6%), Black (8.3%), Hispanic (5.2%), Asian/Pacific Islander (0.9%), Native American (0.7%), and other (1.5%).

Table 3.  Top 10 diagnoses for all discharges and mortality cases of acute exacerbations of chronic obstructive pulmonary disease in 2006

Diagnosis	%
All discharges (Weighted N = 1,254,703)
Essential hypertension	46.2
Heart failure	33.4
Chronic ischemic heart disease	30.6
Disorders of fluid, electrolyte, and acid-base balance	29.7
Diabetes mellitus	26.9
Cardiac dysrhythmias	25.1
Disorders of lipid metabolism	21.8
Other diseases of lung	20.2
Esophageal reflux	14.9
History of tobacco use	14.5
Mortality cases (Weighted N = 53,748)
Other diseases of lung (e.g., respiratory failure, pulmonary collapse, pulmonary insufficiency, acute edema of lung)	63.6
Disorders of fluid, electrolyte, and acid-base balance	56.3
Cardiac dysrhythmias	52.7
Heart failure	46.5
Septicemia, sepsis, and septic shock	35.7
Essential hypertension	32.4
Chronic ischemic heart disease	26.4
Diabetes mellitus	21.8
Hypertensive chronic kidney disease/chronic kidney disease	20.6
Acute renal failure	19.4

Table 4.  Co-morbidities of acute exacerbations of chronic obstructive pulmonary disease discharges in 2006^a

Co-morbidities	Hospital discharges N = 1,254,703 (weighted)
Pre-identified co-morbidities
Acute MI	8.3
Other ischemic heart disease	29.6
Congestive heart failure	32.8
Cerebrovascular disease	4.0
Diabetes with complications	26.3
Lung cancer	3.4
Other cancers	4.3
Cardiac arrhythmias	25.2
Pulmonary circulation disorders	6.9
Weight loss	4.2
Anxiety and/or depression	18.7

^aValues are given as% of all hospital discharges.

Table 5.  Hospital characteristics, hospital region, admission time, mechanical ventilation, and length of stay for discharges of acute exacerbations of chronic obstructive pulmonary disease in 2006^a

Characteristic	Hospital discharges N = 1,254,703 (weighted)
Hospital bed size
Small	18.5
Medium	26.5
Large	54.6
Missing	0.3
Hospital location and teaching status
Rural	24.8
Urban nonteaching	42.8
Urban teaching	32.0
Missing	0.3
Hospital Region
Northeast	18.8
Midwest	25.1
South	44.9
West	11.2
Missing	–
Mechanical ventilation
Non-invasive mechanical ventilation	3.9
Invasive mechanical ventilation	7.9
No ventilation	88.2
Admission period^b
Dec-Mar	36.4
Apr-Nov	54.0
Missing	9.6
Mean length of stay (±SD) (days)	5.9 (±6.1)
Missing (n)	24^c

^aValues are given as% of all hospital discharges, unless otherwise indicated.

^bWhen missing values are excluded percentage in each admission period category are as follows: Dec–Mar (40.3%), Apr–Nov(59.7%).

^cNumber of missing values.

Table 6.  Predictors of hospitalization costs and in-hospital mortality for all discharges of acute exacerbations of chronic obstructive pulmonary disease in 2006

	Hospitalization costs (log transformed)^a		In-hospital mortality^b
Predictors	exp (99% CI)	p-value	OR (99% CI)	p-value
Patient demographics
Age (Referent ≤ 61 yrs)
>61–71 yrs	1.003 (0.994, 1.011)	0.454	1.753 (1.577, 1.950)	<0.001
>71–79 yrs	0.985 (0.976, 0.995)	<0.001	2.517 (2.251, 2.815)	<0.001
≥80 yrs	0.953 (0.944, 0.962)	<0.001	3.894 (3.481, 4.356)	<0.001
Female	1.007 (1.001, 1.012)	0.002	0.918 (0.867, 0.971)	<0.001
Race (Referent: white)
Black	1.030 (1.017, 1.042)	<0.001	0.744 (0.655, 0.846)	<0.001
Hispanic	1.071 (1.056, 1.088)	<0.001	1.001 (0.868, 1.155)	0.981
Asian/Pacific Islander	1.041 (1.004, 1.080)	0.004	0.844 (0.602, 1.182)	0.194
Native American	0.948 (0.897, 1.000)	0.011	1.132 (0.722, 1.775)	0.478
Other	1.024 (0.994, 1.055)	0.041	1.050 (0.806, 1.368)	0.633
Missing Race	1.036 (1.030, 1.043)	<0.001	0.923 (0.858, 0.992)	0.004
Income (Referent <$25,000)
$25,000–34,999	1.044 (1.036, 1.051)	<0.001	1.041 (0.965, 1.123)	0.168
$35,000–44,999	1.057 (1.048, 1.066)	<0.001	1.005 (0.926, 1.092)	0.865
≥$45,000	1.128 (1.117, 1.139)	<0.001	1.038 (0.946, 1.138)	0.303
Primary payer (Referent: Medicare)
Medicaid	0.977 (0.963, 0.988)	<0.001	0.914 (0.791, 1.056)	0.108
Private Insurance	0.993 (0.984, 1.003)	0.073	1.024 (0.926, 1.132)	0.542
Combined category^c	0.984 (0.969, 0.998)	0.004	1.119 (0.951, 1.316)	0.075
Mechanical ventilation (Referent: no ventilation)
Non-invasive mechanical ventilation	1.364 (1.343, 1.386)	<0.001	5.101 (4.601, 5.655)	<0.001
Invasive mechanical ventilation	1.843 (1.785, 1.903)	<0.001	15.305 (14.248, 16.442)	<0.001
Admission period (Referent:Apr-Nov)
Dec-Mar	0.987 (0.981, 0.993)	<0.001	1.103 (1.039, 1.171)	<0.001
Missing admission month	1.074 (1.063, 1.084)	<0.001	0.922 (0.828, 1.027)	0.052
Length of stay^d	1.083 (1.078, 1.089)	<0.001	0.997 (0.993, 1.001)	0.070
Hospital region (Referent: Northeast)
Midwest	0.907 (0.898, 0.916)	<0.001	0.819 (0.742, 0.900)	<0.001
South	0.836 (0.829, 0.844)	<0.001	0.906 (0.833, 0.986)	0.003
West	1.042 (1.027, 1.058)	<0.001	0.853 (0.768, 0.948)	<0.001
Co-morbidities
Deyo-modified Charlson co-morbidity Indexd	1.030 (1.026, 1.033)	0.001	1.168 (1.139, 1.197)	<0.001
Acute Myocardial infarction (MI)	1.055 (1.043, 1.067)	<0.001	1.143 (1.039, 1.257)	<0.001
Other ischemic heart disease (excluding acute MI)	1.033 (1.027, 1.040)	<0.001	0.711 (0.663, 0.761)	<0.001
Congestive heart failure	1.056 (1.048, 1.064)	<0.001	1.078 (1.006, 1.155)	0.005
Cerebrovascular disease	1.046 (1.030, 1.062)	<0.001	1.361 (1.214, 1.526)	<0.001
Diabetes	0.994 (0.986, 1.001)	0.029	0.667 (0.618, 0.719)	<0.001
Lung cancer	1.029 (1.011, 1.046)	<0.001	1.755 (1.532, 2.0117)	<0.001
Cancers excluding lung cancer	0.999 (0.982, 1.017)	0.915	1.120 (0.962, 1.304)	0.055
Cardiac arrhythmias	1.092 (1.084, 1.100)	<0.001	1.418 (1.334, 1.507)	<0.001
Pulmonary circulation disorders	1.095 (1.084, 1.107)	<0.001	1.168 (1.055, 1.293)	<0.001
Weight loss	1.076 (1.052, 1.100)	<0.001	1.970 (1.777, 2.183)	<0.001
Anxiety and /or depression	0.981 (0.974, 0.988)	<0.001	0.768 (0.704, 0.838)	<0.001
Hospital characteristics
Hospital bed size (Referent: small)
Medium	1.052 (1.043, 1.061)	<0.001	0.951 (0.872, 1.038)	0.143
Large	1.031 (1.023, 1.039)	<0.001	0.951 (0.878, 1.029)	0.100
Hospital location and teaching status (Referent: Rural)
Urban nonteaching	1.038 (1.028, 1.048)	<0.001	0.952 (0.874, 1.036)	0.133
Urban teaching	1.042 (1.032, 1.052)	<0.001	0.942 (0.863, 1.028)	0.079

^aMultivariate GLM regression of log transformed costs with Gaussian family and identify link, Log pseudolikelihood = –1,417,313.738, AIC = 11.488.

^bMultivariate GLM regression of in-hospital mortality with binomial family and logit link, Log pseudolikelihood = –170,225.282, AIC = 1.373.

^cCombined category includes self-pay, no charge and other.

^dIncluded as continuous variables.