Table 2 Clinical characteristics of patients with or without PAL in training cohort and validation cohort

Age (years), median (IQR)

58.0 (51.0–65.0)

62.0 (54.0–69.0)

<0.001

57.0 (51.0–65.0)

63.0 (55.5–69.0)

0.002

Gender, n (%)

<0.001

<0.001

 Female

842 (60.1)

123 (47.5)

284 (60.3)

25 (30.5)

 Male

559 (39.9)

136 (52.5)

187 (39.7)

57 (69.5)

BMI (kg/m²), median (IQR)

24.9 (22.9–27.1)

24.0 (22.1–26.0)

<0.001

25.3 (23.0–27.3)

24.1 (22.3–26.6)

0.052

Smoking history, n (%)

<0.001

0.009

 Non-smoker

1074 (76.7)

154 (59.5)

348 (73.9)

49 (59.8)

 Smoker

327 (23.3)

105 (40.5)

123 (26.1)

33 (40.2)

Hypertension, n (%)

0.299

0.872

 No

1023 (73.0)

181 (69.9)

329 (69.9)

58 (70.7)

 Yes

378 (27.0)

78 (30.1)

142 (30.1)

24 (29.3)

Diabetes mellitus, n (%)

0.983

0.760

 No

1211 (86.4)

224 (86.5)

419 (89.0)

72 (87.8)

 Yes

190 (13.6)

35 (13.5)

52 (11.0)

10 (12.2)

COPD, n (%)

0.028

0.219

 No

1391 (99.3)

253 (97.7)

467 (99.2)

80 (97.6)

 Yes

10 (0.7)

6 (2.3)

4 (0.8)

2 (2.4)

Neoadjuvant therapy, n (%)

0.066

0.383

 No

1381 (98.6)

251 (96.9)

460 (97.7)

82 (100.0)

 Yes

20 (1.4)

8 (3.1)

11 (2.3)

0

History of thoracic surgery, n (%)

0.560

0.107

 No

1381 (98.6)

257 (99.2)

469 (99.6)

80 (97.6)

 Yes

20 (1.4)

2 (0.8)

2 (0.4)

2 (2.4)

FEV1 % predicted (%), median (IQR)

105.3 (93.9–116.0)

100.5 (87.1–113.2)

<0.001

105.3 (95.4–115.8)

99.2 (86.9–111.4)

<0.001

MVV % predicted (%), median (IQR)

103.2 (91.1–116.0)

98.2 (85.1–112.1)

<0.001

104.9 (92.5–117.1)

95.2 (85.7–107.3)

<0.001

Blood type, n (%)

0.188

0.199

 A

396 (28.3)

83 (32.0)

140 (29.7)

18 (22.0)

 B

490 (35.0)

88 (34.0)

151 (32.1)

34 (41.5)

 AB

148 (10.6)

17 (6.6)

53 (11.3)

12 (14.6)

 O

367 (26.2)

71 (27.4)

127 (27.0)

18 (22.0)

Lymphocyte (×10⁹/L), median (IQR)

1.79 (1.46–2.20)

1.73 (1.41–2.13)

0.075

1.78 (1.49–2.16)

1.68 (1.43–2.20)

0.306

Albumin (g/L), median (IQR)

59.8 (57.6–61.9)

59.9 (57.6–62.2)

0.395

59.7 (57.4–61.9)

60.1 (57.7–62.1)

0.765

PNI (%), median (IQR)

69.0 (66.1–71.6)

68.8 (65.8–72.0)

0.992

69.0 (66.0–72.0)

68.8 (65.0–72.1)

0.840

ASA score, n (%)

0.005

0.355

 I

143 (10.2)

19 (7.3)

46 (9.8)

4 (4.9)

 II

1228 (87.7)

226 (87.3)

406 (86.2)

74 (90.2)

 III

30 (2.1)

14 (5.4)

19 (4.0)

4 (4.9)

Surgical technique, n (%)

0.316

0.066

 RATS

453 (32.3)

92 (35.5)

176 (37.4)

22 (26.8)

 VATS

948 (67.7)

167 (64.5)

295 (62.6)

60 (73.2)

Surgical procedure, n (%)

<0.001

<0.001

 Sublobar resection

712 (50.8)

68 (26.3)

239 (50.7)

22 (26.8)

 Lobectomy

689 (49.2)

191 (73.7)

232 (49.3)

60 (73.2)

Surgical range, n (%)

0.001

0.288

 Mono-lobe

1219 (87.0)

205 (79.2)

416 (88.3)

69 (84.1)

 Multi-lobe

182 (13.0)

54 (20.8)

55 (11.7)

13 (15.9)

Operation side, n (%)

0.141

0.388

 Left-sided

543 (38.8)

113 (43.6)

183 (38.9)

36 (43.9)

 Right-sided

858 (61.2)

146 (56.4)

288 (61.1)

46 (56.1)

Operation duration (min), median (IQR)

90.0 (70.0–115.0)

110 (85.0–140.0)

<0.001

90.0 (70.0–110.0)

107.5 (80.0–125.0)

<0.001

Number of LNs dissected, median (IQR)

6.0 (4.0–9.0)

8.0 (5.0–12.0)

<0.001

6.0 (4.0–9.0)

7.5 (5.0–12.3)

0.001

Tumor size (cm), median (IQR)

1.3 (0.9–2.0)

1.5 (1.2–2.5)

<0.001

1.3 (0.9–2.0)

2.0 (1.5–3.0)

<0.001