Table 5.
Distribution of demographic, smoking, and clinical variables for internal and external validation data sets
| Internal validation |
External validation |
|||||
|---|---|---|---|---|---|---|
| Characteristic | Cases (n = 89) | Controls (n = 67) | P* | Cases (n = 172) | Controls (n = 153) | P* |
| % Male | 55 | 39 | 0.004 | 13 | 22 | 0.04 |
| Age (mean ± SD) | ||||||
| Males | 62.9 ± 8.9 | 47.6 ± 12.6 | <0.0001 | 46.1 ± 3.0 | 44.1 ± 4.3 | 0.05 |
| Females | 65.2 ± 8.7 | 50.9 ± 15.1 | <0.0001 | 55.2 ± 9.7 | 51.5 ± 10.7 | 0.003 |
| Smoking status, n (%) | ||||||
| Never | 10 (11.3) | 27 (40.3) | <0.0001 | - | - | |
| Former | 38 (42.7) | 12 (17.9) | 148 (86.1) | 66 (43.1) | ||
| Current | 41 (46.0) | 28 (41.8) | 24 (13.9) | 87 (56.9) | <0.0001 | |
| Asbestos, n (%) | 35 (39.3) | 15 (22.4) | 0.025 | 37 (21.5) | 20 (13.1) | 0.05 |
| Dusts, n (%) | 20 (22.5) | 16 (23.9) | 0.84 | 11 (6.4) | 11 (7.2) | 0.78 |
| COPD, n (%) | 19 (21.3) | 1 (1.5) | <0.001 | 14 (8.1) | 4 (2.6) | 0.03 |
| Hay fever,† n (%) | 7 (7.9) | 10 (14.9) | 0.16 | 50 (29.1) | 50 (32.7) | 0.48 |
|
Risk model validation |
AUC (95% CI) |
P
‡
|
AUC (95% CI) |
P
‡
|
||
| Overall | 0.75 (0.67−0.82) | 0.63 (0.57−0.69) | ||||
| Gender | ||||||
| Males | 0.70 (0.58−0.82) | |||||
| Females | 0.75 (0.64−0.85) | 0.61 (0.54−0.67) | ||||
| Early onset | 0.64 (0.64−0.74) | |||||
| Ever smokers | ||||||
| African American model | 0.79 (0.70−0.88) | 0.66 (0.61−0.71) | ||||
| Spitz model | 0.67 (0.57−0.77) | 0.001 | 0.59 (0.52−0.65) | 0.028 | ||
*
P-value from Pearson's Chi-square test (categorical variable) or two-sample t-test (continuous variable).
†
For the external validation, group allergies were used as a proxy for hay fever.
‡
P-value for the comparison of two AUCs (16).