Table 1 Characteristics of patients with t1 tumours, before and after propensity matching. SMD – standardised mean difference

PRE-OPERATIVE

Age, years

Age in years

Over 70

68 [62, 74]

189 (43.9%)

72 [68, 78]

123 (65.8%)

0.54

0.45

< 0.001

< 0.001

72 [67,76]

100 (65.8%)

72 [68,77]

97 (63.8%)

0.15

0.04

0.21

0.72

Sex

Female

226 (52.4%)

106 (56.7%)

0.09

0.38

85 (55.9%)

83 (54.6%)

0.026

0.91

BMI (8, 1)

Overall

26 [23, 29]

27 [23, 30]

0.05

0.54

26.5 [23, 30]

26.5 [23, 30]

0.10

0.38

Underweight

7 (1.6%)

7 (3.7%)

0.15

0.34

4 (2.6%)

7 (4.6%)

0.18

0.51

Normal

156 (36.2%)

66 (35.3%)

50 (32.9%)

50 (32.9%)

Overweight

169 (39.2%)

68 (36.4%)

64 (42.1%)

54 (35.5%)

Obese

91 (21.1%)

45 (24.1%)

33 (21.7%)

40 (26.3%)

Smoking status (1, 0)

Never

48 (11.1%)

16 (8.6%)

0.09

0.41

15 (9.9%)

14 (9.2%)

0.02

> 0.99

Current/ex

382 (88.6%)

171 (91.4%)

137 (90.1%)

138 (90.8%)

Urea, mmol/L (8, 0)

5.5 [4.4, 6.6]

6.1 [4.6, 7.5]

0.10

0.28

5.7 [4.7, 6.7]

6.2 [4.6,7.4]

0.01

0.91

Creatinine, µmol/L (7, 0)

80 [70, 98]

83 [66, 97]

0.10

0.25

80 [69, 95]

83 [66, 97]

0.08

0.46

Haemoglobin, g/dl (7, 0)

13.8 [12.8, 14.7]

13.6 [12.3, 14.6]

0.05

0.61

13.7

[12.6, 14.5]

13.6

[12.3, 14.5]

0.11

0.33

Diabetes status (1. 0)

No

379 (87.9%)

159 (85.0%)

0.09

0.35

127 (83.6%)

130 (85.5%)

0.06

0.75

Yes (any)

51 (11.9%)

28 (15.0%)

25 (16.4%)

22 (14.5%)

Ischaemic heart disease (7, 5)

Yes

72 (16.7%)

43 (23.0%)

0.17

0.07

36 (23.7%)

34 (22.4%)

0.03

0.92

Cardiac failure (6, 5)

Yes

6 (1.4%)

8 (4.3%)

0.18

0.051

0

7 (4.6%)

0.31

0.022

Previous stroke (2, 2)

39 (9.0%)

16 (8.6%)

0.02

0.98

22 (14.5%)

10 (6.6%)

0.26

0.042

ECOG Performance Status (7, 3)

Fully active

265 (61.5%)

86 (46.0%)

0.35

0.001

82 (53.9%)

75 (49.3%)

0.12

0.79

Mobile > 50%

27 (6.3%)

25 (13.4%)

12 (7.9%)

16 (10.5%)

Light work

124 (28.8%)

67 (35.8%)

54 (35.5%)

56 (36.8%)

Limited/immobile

8 (1.9%)

6 (3.2%)

4 (2.6%)

5 (3.3%)

ASA grade (42, 25)

Normal healthy

175 (40.6%)

38 (20.3%)

0.51

< 0.001

59 (38.8%)

37 (24.3%)

0.41

-

Mild disease

161 (37.4%)

80 (42.8%)

58 (38.2%)

65 (42.8%)

Severe disease

52 (12.1%)

43 (23.0%)

16 (10.5%)

32 (21.1%)

Incapacitating/life threatening

1 (0.2%)

1 (0.5%)

0

0

FEV1% predicted (39, 25)

86 [70, 98]

75 [59, 90]

0.36

< 0.001

77 [64, 93]

76.5 [60, 92]

0.01

0.91

FVC % predicted (70, 37)

100 [86, 112]

98 [85, 115]

0.09

0.26

96 [83, 110]

98 [85, 113]

0.11

0.37

Operative priority

Elective

357 (82.8%)

155 (82.9%)

0.002

> 0.99

130 (85.5%)

126 (82.9%)

0.07

0.64

Emergency/urgent

74 (17.2%)

32 (17.1%)

22 (14.5%)

26 (17.1%)

POST OPERATIVE

ITU length of stay (54, 18)

1 [1, 2]

1 [1, 2]

0.001

0.53

1 [1, 2]

max = 76 days

1 [1, 2]

max = 62 days

0.07

0.26

Total length of stay

7 [5, 10]

max 76 days

5 [4, 8]

max 48 days

0.25

0.004

7 [6, 10]

max 76 days

5.5 [4, 8]

max 48 days

0.35

0.002

Post op complications

Yes

72 (17.4%)

22 (11.8%)

0.14

0.15

31 (20.4%)

17 (11.2%)

0.26

0.041

Ventilation (1, 0)

Yes

13 (3.0%)

7 (3.7%)

0.04

0.83

6 (3.9%)

6 (3.9%)

< 0.001

> 0.99

Air leak

Yes

47 (10.9%)

15 (8.0%)

0.10

0.34

20 (13.2%)

11 (7.2%)

0.20

0.13

Pleural effusion

Yes

6 (1.4%)

2 (1.1%)

0.03

> 0.99

2 (1.3%)

2 (1.3%)

< 0.001

> 0.99

Infection

Yes

41 (9.5%)

16 (8.6%)

0.03

0.82

21 (13.8%)

13 (8.6%)

0.17

0.20

Return to theatre

Yes

9 (2.1%)

1 (0.5%)

0.14

0.29

2 (1.3%)

1 (0.7%)

0.07

> 0.99

Histology (1, 0)

Adenocarcinoma

247 (57.3%)

101 (54.0%)

0.34

0.04

88 (57.9%)

81 (53.3%)

0.32

-

Squamous cell

90 (20.9%)

57 (30.5%)

36 (23.7%)

46 (30.3%)

Non-small-cell

18 (4.2%)

3 (1.6%)

5 (3.3%)

3 (2.0%)

Brochiolo-alveolar

14 (3.2%)

1 (0.5%)

5 (3.3%)

1 (0.7%)

Small cell

3 (0.7%)

3 (1.6%)

0

3 (2.0%)

Undifferentiated

1 (0.2%)

0

0

0 (0.4%)

Other

1 (0.2%)

0

17 (11.2%)

18 (11.8%)

Post-operative T-stage (32, 18)

T1

285 (66.1%)

131 (70.1%)

0.21

0.12

95 (62.5%)

108 (71.1%)

0.32

0.036

T2

98 (22.7%)

29 (15.5%)

40 (26.3%)

22 (14.5%)

T3-4

15 (3.5%)

9 (4.8%)

6 (3.9%)

9 (5.9%)

Post-operative N-stage (38, 41)

N0

318 (73.8%)

115 (61.5%)

0.05

0.66

115 (75.7%)

91 (59.9%)

0.16

0.28

N1-2-X

75 (17.4%)

31 (16.6%)

23 (15.1%)

27 (17.8%)

Post-operative M-stage (83, 47)

M0

253 (58.7%)

88 (47.1%)

0.21

0.10

85 (55.9%)

70 (46.1%)

0.12

0.68

M1

5 (1.2%)

3 (1.6%)

2 (1.3%)

2 (1.3%)

MX

90 (20.9%)

49 (26.2%)

37 (24.3%)

39 (25.7%)

SURVIVAL

In-hospital mortality

6 (1.4%)

0

0.17

0.19

2 (1.3%)

0

0.16

0.50

Survival

30 days

426/431

98.8%

187/187

100%

0.15

0.33

151/152

99.3%

152/152

100%

0.12

> 0.99

1 year

386/411

93.9%

152/171

88.9%

0.18

0.057

133/145

91.7%

128/140

91.4%

0.01

0.96

5 years

133/207

64.3%

21/58

36.2%

0.58

< 0.001

47/71

66.2%

20/52

38.5%

0.58

0.003

10 years

22/50

44.0%

0/11

0%

1.25

0.005

3/8

37.5%

0/9

0%

1.10

0.082