Frequent utilization of the emergency department for acute exacerbation of chronic obstructive pulmonary disease

Respiratory Research

Table 4 Negative binomial regression model for factors associated with frequency of emergency department visits for acute exacerbation of chronic obstructive pulmonary disease

Variables	Risk ratio (95% CI)	P value
Age, y
40-54 years	1 [reference]
55-64 years	1.07 (1.06-1.09)	<0.001
65-74 years	1.02 (1.00-1.03)	0.04
75-84 years	0.94 (0.92-0.96)	<0.001
85 years and older	0.86 (0.85-0.88)	<0.001
Male sex
Race/ethnicity
Non-hispanic white	1.08 (1.06-1.09)	<0.001
Non-hispanic black	1.15 (1.13-1.17)	<0.001
Hispanic	1 [reference]
Other	1.01 (0.98-1.03)	0.62
Insurance status
Medicare	1.21 (1.19-1.23)	<0.001
Medicaid	1.34 (1.32-1.36)	<0.001
Private	1 [reference]
Self-pay	1.01 (0.99-1.03)	0.45
Other	1.13 (1.10-1.16)	<0.001
Quartiles for median household income of patient’s ZIP code
1 (lowest)	1.06 (1.05-1.08)	<0.001
2	1.05 (1.03-1.06)	<0.001
3	1.03 (1.01-1.04)	<0.001
4 (highest)	1 [reference]
Patient residence
Counties of ≥ 1 million population	1.03 (1.01-1.05)	<0.001
Counties of 250,000-999,999 population	1.04 (1.02-1.05)	<0.001
Counties of 50,000-249,999 population	1.03 (1.01-1.06)	0.007
Counties of < 50,000 population	1 [reference]
State
California	1.02 (1.02-1.03)	<0.001
Florida	1 [reference]
Selected comorbidities
Congestive heart failure	1.05 (1.04-1.06)	<0.001
Pulmonary circulation disorders	1.13 (1.09-1.17)	<0.001
Diabetes, uncomplicated	1.04 (1.03-1.05)	<0.001
Obesity	0.97 (0.96-0.99)	<0.001
Depression	1.08 (1.07-1.10)	<0.001
Psychoses	1.08 (1.06-1.10)	<0.001
Drug abuse	1.18 (1.15-1.21)	<0.001

Abbreviations: COPD chronic obstructive pulmonary disease, ED emergency department CI confidence interval.
Bold results are statistically significant.

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