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23

Tables

Table 1 Characteristics of the patients before and after propensity score matching

Table 2 Outcomes after propensity score matching

Table 3 Sensitivity analysis between different postoperative periods

24

Figure Legends

Figure 1: Flowchart of patient recruitment

Figure 2: Annual number of laparoscopic and open inguinal hernia repair procedures

Supplementary Resources

Online resource 1 MEDIS-DC code for comorbidities

Online resource 2 Outcomes before propensity score matching

Online resource 3 Outcomes of propensity score matching in 2009-2015 and 2016-2020

Online resource 4 Sensitivity analysis with multilevel model

25

Figure 1 Flowchart of the patient recruitment

Patients who underwent IHR† for the first time except for cases of femoral hernia (n=24,471)

Excluded (n=8,743)

19 years and younger (n=4,498)

Other operation performed at the same time (n=2,713)

Emergency operation (n=523)

Recurrent operation (n=228)

Previous laparotomy or laparoscopic surgery (n=71)

Retropubic or robot-assisted laparoscopic radical prostatectomy (n=222)

No data (n=488)

Eligible patients (n=15,728)

LIHR‡ (n=6,512)

OIHR§ (n=9,216)

Propensity score matching

OIHR§ (n=6,060)

LIHR‡ (n=6,060)

†IHR=inguinal

hernia repair,

‡ LIHR=laparoscopic

§ OIHR=open

inguinal hernia repair

inguinal hernia repair

Figure 2 Annual number of laparoscopic and open inguinal hernia repair

N 1600

1400

1200

1000

800

600

400

200

2009

LIHR

15

OIHR‡ 87

2011

40

238

2012

83

503

LIHR=laparoscopic inguinal hernia repair,

‡ OIHR=open

2010

33

168

inguinal hernia repair

six months period

2013

166

740

2014

317

746

2015

488

998

2016 2017

791 1,060

1,109 1,271

2018 2019

1,276 1,512

1,347 1,355

2020

731

654

Table 1 Characteristics of the patients before and after propensity score matching

Before propensity score matching (n=15,728)

Laparoscopic (n=6,512)

Open (n=9,422)

After propensity score matching (n=12,120 )

Standardied difference

Laparoscopic (n=6,060)

Open (n=6,060)

Standardied difference

Sex male, n(%)

6,002 (92.2)

8,421 (91.4)

2.9

5,579 (92.1)

5,560 (91.8)

1.1

Age (years), mean (SD)†

52.6 (11.9)

53.0 (12.3)

3.6

52.4 (11.9)

52.6 (12.5)

1.1

909 (14.0)

449 (4.9)

31.5

515 (8.5)

413 (6.8)

5.8

Myocardial infarction

30 (0.5)

80 (0.9)

29 (0.5)

32 (0.5)

Congestive heart failure

15 (0.2)

36 (0.4)

15 (0.2)

18 (0.3)

0.9

hernia, n(%)

Bilateral

Comorbidities, n(%)

358 (5.5)

568 (6.2)

2.8

337 (5.6)

351 (5.8)

Chronic obstructive pulmonary disease

1,169 (18.0)

1,480 (16.1)

1,072 (17.7)

1,015 (16.7)

2.5

Mild liver disease

1,025 (15.7)

1,408 (15.3)

1.3

958 (15.8)

919 (15.2)

1.8

191 (2.9)

272 (3.0)

0.1

179 (3.0)

179 (3.0)

146 (2.2)

232 (2.5)

1.8

138 (2.3)

135 (2.2)

0.3

Renal disease

85 (1.3)

182 (2.0)

5.3

82 (1.4)

95 (1.6)

1.7

Cancer

184 (2.8)

482 (5.2)

12.3

184 (3.0)

191 (3.2)

0.6

0 (0-1)

0 (0-1)

6.6

0 (0-1)

0 (0-1)

0.7

Corticosteroid

497 (7.6)

377 (4.1)

15

393 (6.5)

318 (5.2)

5.3

Anticoagulant

311 (4.8)

586 (6.4)

303 (5.0)

328 (5.4)

1.8

392 (6.0)

481 (5.2)

3.5

358 (5.9)

334 (5.5)

1.7

0-19

559 (8.6)

1,248 (13.5)

15.9

557 (9.2)

650 (10.7)

4.9

20-99

211 (3.2)

611 (6.6)

15.7

211 (3.5)

209 (3.4)

0.2

100-199

826 (12.7)

1,359 (14.7)

785 (13.0)

898 (14.8)

5.4

200-299

731 (11.2)

809 (8.8)

8.2

689 (11.4)

617 (10.2)

300-499

2,274 (34.9)

2,661 (29.0)

13

2,072(34.2)

1,966 (32.4)

3.8

≥500

1,911 (29.3)

2,528 (27.4)

4.2

1,746 (28.8)

1,720 (28.3)

Cerebrovascular disease

Diabetes without complications

Diabetes with complications

Charlson comorbidities index score, median (IQR)‡

Medication, n(%)

Facility information, n(%)

University hospital

Number of bed

Year, n(%)

2009

15 (0.2)

87 (0.9)

9.4

15 (0.2)

22 (0.4)

1.5

2010

33 (0.5)

168 (1.8)

12.3

33 (0.5)

35 (0.6)

0.3

2011

40 (0.6)

238 (2.6)

15.7

40 (0.7)

47 (0.8)

0.9

2012

83 (1.3)

503 (5.5)

23.3

83 (1.4)

82 (1.4)

2013

166 (2.5)

740 (8.0)

24.8

166 (2.7)

168 (2.8)

0.1

2014

317 (4.9)

746 (8.1)

13.1

317 (5.2)

300 (5.0)

1.1

2015

488 (7.5)

998 (10.8)

11.6

486 (8.0)

532 (8.8)

2.6

2016

791 (12.1)

1,109 (12.0)

0.3

745 (12.3)

868 (14.3)

6.2

2017

1,060 (16.3)

1,271 (13.8)

985 (16.3)

1,025 (16.9)

1.9

2018

1,276 (19.6)

1,347 (14.6)

13.3

1,174 (19.4)

1,157 (19.1)

0.7

2019

1,512 (23.2)

1,355 (14.7)

21.9

1,362 (22.5)

1,232 (20.3)

5.5

2020

731 (11.2)

654 (7.1)

14.4

654 (10.8)

592 (9.8)

3.6

† SD=standard deviation, ‡ IQR=interquartile range

Table 2 Outcomes after propensity score matching

Unadjusted analysis

Adjusted analysis

Laparoscopic

Open

OR†

CI‡ (95%)

OR†

CI‡ (95%)

Surgical site infection

172 (2.6)

350 (3.8)

0.69

0.57-0.83

<0.0001

0.70

0.56-0.86

0.0007

Acute postoperative pain

390 (6.0)

670 (7.3)

0.81

0.71-0.93

0.0016

0.69

0.60-0.79

<0.0001

Bleeding

47 (0.7)

93 (1.0)

0.71

0.50-1.01

0.0601

0.84

0.56-1.25

0.3863

Seroma / Edema

6 (0.1)

16 (0.2)

0.53

0.21-1.37

0.1854

0.39

0.12-1.24

0.1096

Fever

32 (0.5)

42 (0.5)

1.08

0.68-1.71

0.7475

1.00

0.59-1.69

0.9956

Pneumonia

9 (0.1)

11 (0.1)

1.16

0.48-2.80

0.7441

1.13

0.38-3.41

0.8261

Urinary tract infection

42 (0.6)

44 (0.5)

1.35

0.87-2.07

0.1620

1.21

0.75-1.95

0.4309

Bowel obstruction

5 (0.08)

4 (0.04)

1.77

0.48-6.60

0.3950

2.08

0.78-9.12

0.3303

Chronic postoperative pain

284 (4.4)

581 (6.3)

0.68

0.59-0.78

<0.0001

0.83

0.70-0.98

0.0291

46 (0.7)

117 (1.3)

0.53

0.39-0.78

0.0007

0.68

0.45-1.01

0.0558

Complication, n (%)

Recurrence, n (%)

Unadjusted

Adjusted

Laparoscopic

Length of hospital stay (day)

Open

Laparoscopic

Means ±SD

Means ±SD

Difference±SE

2.92±1.91

2.98±2.69

0.06±0.03

†OR odds ratio, ‡CI confidential interval, §SD standard deviation, ¶ SE standard error

Open

Means ±SD

Means ±SD§

Difference±SE¶

0.1013

2.91±1.94

2.97±2.61

0.06±0.04

0.1307

Table 3 Sensitivity analysis with changing postoperative period

Unadjusted analysis

OR

CI (95%)

Surgical site infection

0.69

Acute postoperative pain

Bowel obstruction

Adjusted analysis

OR†

CI (95%)‡

0.57-0.83

<0.000

0.70

0.56-0.86

0.0007

0.81

0.71-0.93

0.0016

0.69

0.60-0.79

<0.0001

1.77

0.48-6.60

0.3950

2.08

0.78-9.12

0.3303

Surgical site infection

0.77

0.65-0.92

0.0041

0.79

0.64-0.96

0.0159

Acute postoperative pain

0.86

0.80-0.94

0.0005

0.82

0.75-0.90

<0.0001

Bowel obstruction

1.18

0.36-3.87

0.7852

1.10

0.32-3.90

0.8728

Surgical site infection

0.77

0.65-0.91

0.0020

0.78

0.64-0.95

0.0114

Acute postoperative pain

0.86

0.80-0.94

0.0004

0.82

0.74-0.90

<0.0001

Bowel obstruction

1.18

0.36-3.87

0.7852

1.11

0.32-3.90

0.8728

above 90 days

0.68

0.59-0.78

<0.0001

0.83

0.70-0.98

0.0291

above 120 days

0.67

0.58-0.79

<0.0001

0.83

0.70-0.98

0.0324

above 180 days

0.67

0.58-0.78

<0.0001

0.83

0.70-0.98

0.0324

Complication within 30 days

Complication within 60 days

Complication within 90 days

Chronic postoperative pain

†OR odds ratio, ‡CI confidential interval

Online resource 1 MEDIS-DC codes for complications

Surgical site infection

6829010, 6829014, 6829029, 6869050, 7290026, 8799006, 8833977, 8835326, 8835353, 8836665, 8836796, 8839756, 8845681, 9983005 ,

9985006, 9985039

Acute postoperative pain

8835913 8836793 8838060 8845802 9989020 8832414

Bleeding

4590002, 8830697, 8833916, 8835847, 9249027

Edema

8848922, 8830618 6072008 8830705 6248005 8835852

Fever

7806011, 8835356

Urinary tract infection

5950005, 5959003, 5959015, 5978015, 5990009, 8838561

Vas deferens injury

8835836

Intestinal injury

8834767, 8837685

pneumonia

9973011, 4860030

Bowel obstruction

8835320, 9974018

Chronic postoperative pain

8835913 8836793 8838060 8845802 9989020 8847821

Online resource 2 Outcomes before propensity score matching

Laparoscopic

Open

Unadjusted analysis

(n=6,512)

(n=9,216)

OR†

CI‡ (95%)

Surgical site infection

172 (2.6)

350 (3.8)

0.69

0.57-0.83

<0.0001

Acute postoperative pain

390 (6.0)

670 (7.3)

0.81

0.71-0.93

0.0016

Bleeding

47 (0.7)

93 (1.0)

0.71

0.50-1.01

0.0601

Seroma / Edema

6 (0.1)

16 (0.2)

0.53

0.21-1.37

0.1854

Fever

32 (0.5)

42 (0.5)

1.08

0.68-1.71

0.7475

Pneumonia

9 (0.1)

11 (0.1)

1.16

0.48-2.80

0.7441

Urinary tract infection

42 (0.6)

44 (0.5)

1.35

0.87-2.07

0.1620

Bowel obstruction

5 (0.08)

4 (0.04)

1.77

0.48-6.60

0.3950

Chronic postoperative pain

284 (4.4)

581 (6.3)

0.68

0.59-0.78

<0.0001

46 (0.7)

117 (1.3)

0.53

0.39-0.78

0.0007

Complication, n (%)

Recurrence, n (%)

Difference±SE¶

88.3 ±1.17

<0.0001

0.06±0.03

0.1013

Anesthesia

Time (min),mean (SD§)

141 (±49.4)

51.4 (±54.8)

Missing data, n (%)

2,981 (45.8)

4,676 (50.7)

2.92±1.91

2.98±2.69

Length of hospital stay (day),

mean ±SD§

†OR odds ratio, ‡CI confidential interval, §SD standard deviation, ¶ SE standard error

Online resource 3 Outcomes of propensity score matching in 2009-2015 and 2016-2020

Adjusted analysis in 2009-2015

Adjusted analysis in 2016-2020

OR†

CI‡ (95%)

OR†

CI‡ (95%)

Surgical site infection

0.58

0.36-0.96

0.0323

0.73

0.58-0.91

0.0061

Acute postoperative pain

0.69

0.49-0.95

0.0229

0.69

0.59-0.80

<0.0001

Bleeding

0.93

0.37-2.36

0.8819

0.79

0.50-1.24

0.3043

Seroma

NA§

0.64

0.21-2.00

0.4464

Fever

0.84

0.94

0.53-1.67

0.8313

Pneumonia

NA§

1.07

0.31-3.71

0.9183

Urinary tract infection

2.47

1.06

0.63-1.81

0.8191

Bowel obstruction

NA§

2.26

0.40-13.00

0.3601

Chronic postoperative pain

0.71

0.54-0.84

0.0170

0.90

0.74-1.11

0.3412

0.50

0.26-0.98

0.0422

0.91

0.57-1.45

0.6681

Laparoscopic

Open

Laparoscopic

Open

Means ±SD§

Means ±SD§

Difference±SE¶

Means ±SD§

Means ±SD§

Difference±SE¶

2.96±1.87

3.17±2.83

0.21±0.09

0.0240

2.89±1.95

2.96±2.55

0.07±0.05

0.1333

Complication

Recurrence

Length of hospital stay (day)

†OR odds ratio, ‡CI confidential interval, §NA not available

0.27-2.59

0.7627

0.87-7.00

0.0882

Online resource 4 Sensitivity analysis with multilevel model

Unadjusted analysis

Adjusted analysis

OR†

CI‡ (95%)

OR†

CI‡ (95%)

Surgical site infection

0.69

0.57-0.83

<0.0001

0.91

0.69-1.20

0.4795

Acute postoperative pain

0.81

0.71-0.93

0.0016

0.66

0.55-0.80

<0.0001

Bleeding

0.71

0.50-1.01

0.0601

0.78

0.46-1.32

0.358

Seroma / Edema

0.53

0.21-1.37

0.1854

Non-estimated value

Fever

1.08

0.68-1.71

0.7475

Non-estimated value

Pneumonia

1.16

0.48-2.80

0.7441

Non-estimated value

Urinary tract infection

1.35

0.87-2.07

0.1620

1.44

0.86-2.43

0.1672

Bowel obstruction

1.77

0.48-6.60

0.3950

3.10

0.71-13.07

0.133

Chronic postoperative pain

0.68

0.59-0.78

<0.0001

0.85

0.71-1.01

0.0577

0.53

0.39-0.78

0.0007

0.70

0.48-1.04

0.0782

Complication

Recurrence

†OR odds ratio, ‡CI confidential interval

...