Table 1 Patient demographics before and after propensity score (PS) matching

518,058

100.00

516,100

99.62

1958

0.38

18,601

100.00

16,910

90.91

1691

9.09

Age

<0.001

0.928

< 25

3092

0.60

2913

0.56

179

9.14

1194

6.42

1083

6.40

111

6.56

25–34

15,361

2.97

14,951

2.90

410

20.94

3214

17.28

2933

17.34

281

16.62

35–44

53,986

10.42

53,436

10.35

550

28.09

5568

29.93

5069

29.98

499

29.51

45–54

127,935

24.70

127,351

24.68

584

29.83

6059

32.57

5494

32.49

565

33.41

55–64

136,540

26.36

136,363

26.42

177

9.04

1894

10.18

1717

10.15

177

10.47

≧65

181,144

34.97

181,086

35.09

58

2.96

672

3.61

614

3.63

58

3.43

59.22

13.15

59.29

13.11

42.01

12.03

44.14

11.86

44.19

11.87

43.60

11.78

<0.001

0.659

Low-income household

5010

0.97

5009

0.97

1

0.05

3

0.02

2

0.01

1

0.06

≦17,280

35,033

6.77

34,873

6.77

160

8.17

1826

9.82

1670

9.88

156

9.23

17,281 ~ 22,800

295,781

57.20

295,390

57.34

391

19.97

4312

23.18

3922

23.19

390

23.06

22,801 ~ 28,800

77,247

14.94

77,044

14.96

203

10.37

2011

10.81

1819

10.76

192

11.35

28,801 ~ 36,300

30,974

5.99

30,745

5.97

229

11.70

2015

10.83

1829

10.82

186

11.00

36,301 ~ 45,800

33,977

6.57

33,470

6.50

507

25.89

4128

22.19

3739

22.11

389

23.00

45,801 ~ 57,800

19,896

3.85

19,584

3.80

312

15.93

2540

13.66

2311

13.67

229

13.54

≧57,801

19,206

3.71

19,051

3.70

155

7.92

1766

9.49

1618

9.57

148

8.75

Missing data

934

934

<0.001

0.181

Level 1

141,455

27.35

140,779

27.33

676

34.53

6593

35.44

5998

35.47

595

35.19

Level 2 & 3

231,299

44.73

230,365

44.72

934

47.70

9149

49.19

8334

49.28

815

48.20

Level 4 & 5

94,836

18.34

94,589

18.36

247

12.61

2145

11.53

1944

11.50

201

11.89

Level 6 & 7

49,533

9.58

49,432

9.60

101

5.16

714

3.84

634

3.75

80

4.73

Missing data

935

935

0.318

0.158

No

503,285

97.15

501,375

97.15

1910

97.55

18,200

97.84

16,554

97.89

1646

97.34

Yes

14,773

2.85

14,725

2.85

48

2.45

401

2.16

356

2.11

45

2.66

0.218

0.085

No

440,556

85.04

438,871

85.04

1685

86.06

16,425

88.30

14,954

88.43

1471

86.99

Yes

77,502

14.96

77,229

14.96

273

13.94

2176

11.70

1956

11.57

220

13.01

<0.001

0.247

0

8776

1.69

8751

1.70

25

1.28

233

1.25

212

1.25

21

1.24

1 ~ 3

129,044

24.91

128,410

24.88

634

32.38

6438

34.61

5881

34.78

557

32.94

4 ~ 6

148,079

28.58

147,421

28.56

658

33.61

6130

32.96

5581

33.00

549

32.47

7 ~ 9

125,612

24.25

125,197

24.26

415

21.20

3858

20.74

3493

20.66

365

21.58

≧10

106,547

20.57

106,321

20.60

226

11.54

1942

10.44

1743

10.31

199

11.77

6.33

3.78

6.33

3.78

5.41

3.39

5.18

3.29

5.15

3.28

5.43

3.42

<0.001

0.438

0

359,786

69.45

358,301

69.42

1485

75.84

14,358

77.19

13,075

77.32

1283

75.87

1

79,434

15.33

79,144

15.34

290

14.81

2737

14.71

2480

14.67

257

15.20

2

52,368

10.11

52,232

10.12

136

6.95

1118

6.01

1009

5.97

109

6.45

≧3

26,470

5.11

26,423

5.12

47

2.40

388

2.09

346

2.05

42

2.48

0.54

0.98

0.54

0.98

0.37

0.76

0.34

0.73

0.34

0.73

0.36

0.75