Table 2 Predictors of hospital admission among patients presenting to ER with COPD as the primary diagnosis using logistic regression

Age

  < 50

Ref

Ref

 50- <65

2.01 (1.92, 2.09)

<0.0001

1.45 (1.38, 1.51)

<0.0001

 65- <80

3.42 (3.23, 3.61)

<0.0001

1.67 (1.57, 1.77)

<0.0001

  ≥ 80

4.95 (4.65, 5.27)

<0.0001

1.90 (1.77, 2.03)

<0.0001

Gender

 Female (ref)

Ref

Ref

 Male

0.98 (0.96, 1.00)

0.0309

0.91 (0.89, 0.93)

<0.0001

Median household income

 1st quartile (< $38,999)

Ref

Ref

 2nd quartile ($39,000 to $47,999)

1.14 (1.06, 1.23)

0.0009

1.08 (1.00, 1.18)

0.0509

 3rd quartile ($48,000 to $62999)

1.40 (1.29, 1.53)

<0.0001

1.17 (1.07, 1.29)

0.0012

 4th quartile ($63,000 or more)

2.08 (1.86, 2.33)

<0.0001

1.45 (1.29, 1.63)

<0.0001

Primary payer

 Medicare (ref)

Ref

Ref

 Medicaid

0.52 (0.49, 0.54)

<0.0001

0.91 (0.86, 0.96)

0.0005

 Private insurance

0.63 (0.60, 0.66)

<0.0001

0.98 (0.93, 1.03)

0.4990

 Self-pay/no charge

0.30 (0.28, 0.31)

<0.0001

0.70 (0.66, 0.74)

<0.0001

 Other

0.63 (0.55, 0.72)

<0.0001

1.04 (0.93, 1.15)

0.5203

Patient location (residence)

 Micropolitan/not metropolitan

Ref

Ref

 Metropolitan (large or small)

1.70 (1.54, 1.89)

<0.0001

1.42 (1.27, 1.58)

<0.0001

Hospital Region

 Northeast

Ref

Ref

 Midwest

0.54 (0.45, 0.64)

<0.0001

0.60 (0.51, 0.71)

<0.0001

 South

0.66 (0.56, 0.79)

<0.0001

0.80 (0.67, 0.95)

0.0106

 West

0.58 (0.48, 0.69)

<0.0001

0.63 (0.52, 0.76)

<0.0001

Teaching status of hospital

 Metropolitan non-teaching or non-metropolitan

Ref

Ref

 Metropolitan teaching

1.34 (1.17, 1.53)

<0.0001

1.14 (0.99, 1.30)

0.0687

Comorbidities

 CHD (ref: no)

3.77 (3.55, 4.01)

<0.0001

1.89 (1.80, 1.99)

<0.0001

 Hyperlipidemia (ref: no)

4.30 (3.98, 4.64)

<0.0001

2.35 (2.19, 2.51)

<0.0001

 Renal failure (ref: no)

6.90 (6.33, 7.53)

<0.0001

3.10 (2.83, 3.39)

<0.0001

 CHF (ref: no)

3.96 (3.73, 4.21)

<0.0001

2.13 (2.02, 2.25)

<0.0001

 Gout (ref: no)

4.61 (4.08, 5.22)

<0.0001

1.87 (1.64, 2.14)

<0.0001

 Diabetes (ref: no)

2.24 (2.14, 2.33)

<0.0001

1.19 (1.15, 1.24)

<0.0001

 Hypertension (ref: no)

3.50 (3.31, 3.69)

<0.0001

1.93 (1.84, 2.02)

<0.0001

 Osteoarthritis (ref: no)

6.83 (6.07, 7.67)

<0.0001

5.02 (4.42, 5.70)

<0.0001