Table 2 Baseline characteristics before and after propensity score matching
Characteristics | Before PSM | After PSM | ||
|---|---|---|---|---|
Case (N = 466) | Control (N = 455) | Case (N = 445) | Control (N = 445) | |
Age, n (%)a | ||||
 \(\overline{\text{x} }\)± s (years) | 60.59 ± 11.36 | 58.11 ± 10.08 | 61.51 ± 10.31 | 58.11 ± 10.19 |
≤ 40 | 29 (6.22) | 29 (6.37) | 17 (3.82) | 29 (6.52) |
40–55 | 107 (22.96) | 116 (25.49) | 99 (22.25) | 116 (26.07) |
> 55 | 330 (70.82) | 310 (68.14) | 329 (73.93) | 300 (67.41) |
Sex, n (%)b | Â | Â | Â | Â |
 Male | 314 (67.38) | 296 (65.1) | 296 (66.52) | 296 (66.52) |
 Female | 152 (32.62) | 159 (34.9) | 149 (33.48) | 149 (33.48) |
Smoking, n (%)c | ||||
 No | 186 (39.91) | 296 (65.05) | 179 (40.22) | 286 (64.27) |
 Yes | 280 (60.09) | 159 (34.95) | 266 (59.78) | 159 (35.73) |
Alcohol drinking, n (%)d | ||||
 No | 342 (73.39) | 336 (73.85) | 328 (73.71) | 326 (73.26) |
 Yes | 124 (26.61) | 119 (26.15) | 117 (26.29) | 119 (26.74) |
AN chewing, n (%)e | ||||
 No | 435 (93.35) | 433 (95.16) | 415 (93.26) | 423 (95.06) |
 Yes | 31 (6.65) | 22 (4.84) | 30 (6.74) | 22 (4.94) |
COPD, n (%) | ||||
 No | 389 (83.48) | - | 369 (82.92) | - |
 Yes | 47 (10.09) | - | 47 (10.56) | - |
 Unknown | 30 (6.43) |  | 29 (6.52) |  |
Histology types, n (%) | ||||
 Adenocarcinoma | 310 (66.52) | - | 295 (66.29) | - |
 Squamous cell carcinoma | 73 (15.67) | - | 72 (16.18) | - |
 Small cell carcinoma | 44 (9.44) | - | 43 (9.66) | - |
 Others | 39 (8.37) | - | 35 (7.87) | - |
Pathologic stage, n (%) | ||||
 I | 138 (29.61) | - | 129 (28.99) | - |
 II | 16 (3.43) | - | 16 (3.60) | - |
 III | 74 (15.88) | - | 71 (15.96) | - |
 IV | 238 (51.08) | - | 229 (51.45) | - |