Table 2 Baseline characteristics for study population from the NRD

N (%)

14,373 (0.11)

12,913,858 (99.89)

Age (years)

36.50 ± 0.20

52.35 ± 0.01

< 0.001

Sex (%)

< 0.001

 Female

63.09

58.76

 Male

36.91

41.24

House income (%)

< 0.001

 0-25th percentile ($1 - $45,999)

21.94

27.32

 26th to 50th percentile ($46,000 - $58,999)

26.51

27.46

 51st to 75th percentile ($59,000 - $78,999)

26.85

24.91

 76th to 100th percentile ($79,000 or more)

24.70

20.30

Primary expected payer (%)

< 0.001

 Medicare

28.07

41.36

 Medicaid

25.99

20.80

 Private insurance

40.47

30.72

 Self-pay

2.09

3.68

 No charge

0.22

0.44

 other

3.17

2.99

Patient location (%)

< 0.001

 ”central” counties of metro areas of ≥ 1 million population

25.41

27.97

 ”fringe” counties of metro areas of ≥ 1 million population

27.84

25.61

 counties in metro areas of 250,000-999,999 population

23.65

22.02

 counties in metro areas of 50,000-249,999 population

9.81

9.84

 micropolitan counties

7.61

8.33

 not metropolitan or micropolitan counties

5.69

6.23

Dead (%)

1.76

1.72

0.729

Elective

< 0.001

 Elective admission

31.92

23.29

 Nonelective admission

68.08

76.71