Patient demographics
| Training set | European validation set | Chinese validation set | |||||||
| Cases | Controls | p-value | Cases | Control | p-value | Cases | Control | p-value | |
| Subjects | 102 | 265 | 179 | 137 | 30 | 15 | |||
| Age years | 67 (51–83) | 62 (49–82) | p<0.0001 | 65 (23–89) | 63 (50–87) | 0.0130 | 64 (40–79) | 33 (23–51) | p<0.0001 |
| Sex | 0.182 | 0.037 | 0.053 | ||||||
| Male | 70 (68.6) | 162 (61.1) | 132 (73.7) | 86 (62.8) | 21 (70.0) | 6 (40.0) | |||
| Female | 32 (31.4) | 103 (38.9) | 47 (26.3) | 51 (37.2) | 9 (30.0) | 9 (60.0) | |||
| Smoking status | p<0.0001§ | p<0.0001§ | p<0.001§ | ||||||
| Current smoker# | 36 (35.3) | 117 (44.2) | 75 (41.9) | 57 (41.6) | 11 (36.7) | 0 (0.0) | |||
| Former smoker | 7 (6.9) | 148 (55.8) | 35 (19.6) | 80 (58.4) | 4 (13.3) | 1 (6.7) | |||
| Never-smoker | 6 (5.9) | 9 (5.0) | 14 (46.7) | 14 (93.3) | |||||
| Unknown | 53 (52.0) | 60 (33.5) | 1 (3.3) | 0 (0.0) | |||||
| Smoking pack-years¶ | 40 (2–129) | 20 (1–138) | 0.010 | 41 (4–182) | 20 (1–120) | p<0.0001 | 30 (15–80) | 10 (NA) | ƒ |
| Years since quitting smoking+ | 13 (2–41) | 17 (1–50) | 0.267 | 18 (1–42) | 17 (1–58) | 0.394 | 7 (3–10) | 10 (NA) | ƒ |
Data are presented as n, median (range) or n (%), unless otherwise stated. #: smokers reporting quitting within 1 year prior to study inclusion were considered to be current smokers; ¶: reported in smokers only; this information was missing for five cases in the training set; +: reported in former smokers only; this information was missing for five controls in the training set, and in five patients (n=4 cases, n=1 control) in the European validation set; §: this analysis included only patients in the current and former smoker categories; ƒ: not calculated as there was only one control subject with history of smoking in this set.