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Table 1 Patient characteristics across hospital volume groups

From: Volume-based referral for cardiovascular procedures in the United States: a cross-sectional regression analysis

Characteristics

Hospital CABG Volume

 

Hospital PCI Volume

 
 

Overall

Low (<450)

High (≥450)

P

Overall

Low (<400)

High (≥400)

P

% of patients (weighted)

100.0

38.4

61.6

-

100.0

14.0

86.0

-

% of hospital year groups*

100.0

69.8

30.2

-

100.0

45.1

54.9

-

Mean age, (SD) years

66.0 (0.07)

65.9 (0.08)

66.1 (0.11)

0.12

64.2 (0.08)

63.7 (0.12)

64.2 (0.09)

<0.001

Age

   

0.11

   

<0.001

   Less than 65

41.1

41.7

40.7

 

48.7

50.7

48.3

 

   65–74 years

34.5

34.2

34.7

 

28.8

27.6

29.0

 

   75 years of age and older

24.4

24.1

24.6

 

22.5

21.7

22.6

 

Male

69.5

69.4

69.5

0.90

65.5

64.4

65.7

<0.001

Race

   

0.014

   

0.016

   White

64.2

59.2

67.3

 

63.3

56.7

64.4

 

   Black

3.8

3.8

3.9

 

4.5

5.1

4.4

 

   Other

7.5

9.5

6.2

 

7.3

10.1

6.9

 

   Race not reported/missing

24.5

27.6

22.6

 

24.9

28.1

24.4

 

Primary payer

   

<0.001

   

<0.001

   Medicare

53.8

51.9

55.0

 

49.0

45.7

49.5

 

   Medicaid

4.0

4.7

3.5

 

4.0

5.3

3.8

 

   Private

37.3

37.4

37.3

 

41.2

40.6

41.4

 

   Other/missing

4.9

6.0

4.2

 

5.8

8.4

5.4

 

Diabetes

29.5

29.8

29.3

0.14

24.9

25.4

24.8

0.12

Hypertension

58.6

58.0

58.9

0.098

54.1

53.0

54.3

0.022

COPD

17.3

17.5

17.2

0.37

11.2

11.9

11.0

0.002

Congestive heart failure

17.6

17.5

17.7

0.64

9.9

10.7

9.8

<0.001

Peripheral vascular disease

7.6

7.5

7.6

0.55

5.6

5.4

5.6

0.43

Renal disease

6.0

5.8

6.1

0.11

2.6

2.9

2.5

<0.001

Coronary disease

   

<0.001

   

<0.001

   MI as primary diagnosis

20.3

20.1

20.4

 

31.0

37.6

29.9

 

   MI as secondary diagnosis

5.7

6.3

5.3

 

4.5

5.0

4.4

 

   Other coronary artery disease

65.6

65.5

65.7

 

60.2

53.1

61.4

 

   No coronary disease

8.4

8.1

8.6

 

4.3

4.3

4.3

 

Admission type

   

<0.001

   

<0.001

   Emergency

23.7

23.8

23.6

 

31.9

36.9

31.1

 

   Urgent

25.2

22.1

27.1

 

26.1

23.6

26.5

 

   Elective

41.5

38.6

43.4

 

32.3

21.5

34.1

 

   Other/missing

9.6

15.6

5.9

 

9.6

18.1

8.2

 

Arrived by inter-hospital transfer

   

<0.001

   

<0.001

   Yes

18.0

11.5

22.0

 

18.2

9.0

19.7

 

   No

78.8

85.4

74.7

 

78.4

88.4

76.8

 

   Unknown

3.2

3.2

3.3

 

3.4

2.7

3.6

 

Year

   

0.59

   

0.17

   1998

25.4

26.0

25.1

 

22.0

25.6

21.4

 

   1999

23.7

21.5

25.1

 

22.2

24.2

21.9

 

   2000

25.5

25.2

25.7

 

26.0

25.6

26.1

 

   2001

25.3

27.4

24.0

 

29.8

24.6

30.6

 

Procedure-specific variables

        

   Same admission PCI

2.8

3.3

2.4

<0.001

-

-

-

-

   Concomitant valve procedure

10.6

9.5

11.3

<0.001

-

-

-

-

   Internal mammary artery graft

16.8

13.4

18.8

<0.001

-

-

-

-

   Multivessel PCI

-

-

-

-

14.5

14.8

12.6

<0.001

  1. Unless noted otherwise, findings are expressed as percentages
  2. Percentages may not sum to 100 due to rounding
  3. * Hospital year groups refer to the number of hospitals that contributed data in each year of the NIS. A hospital participating in the NIS over the 3 year period would be considered to have contributed 3 hospital year groups to the analysis.
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BMC Health Services Research

ISSN: 1472-6963

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