Table 4.
AUC, Sensitivity, and Specificity of Identifying DA+ Using IFN-γ Promoter Methylation Level as a Predictor
| Stratification variable | Category | Univariate modela | Multivariate model | ||||
|---|---|---|---|---|---|---|---|
| AUC | Sensitivityb | Specificityb | AUC | Sensitivityb | Specificityb | ||
| — | — | 70.6% | 60.0% | 81.3% | 87.4%c | 77.5% | 80.0% |
| DI exposed | HDI | 65.3% | 52.6% | 82.1% | 83.7%d | 63.2% | 81.8% |
| Smoking status | Never | 74.4% | 60.0% | 87.1% | 88.1%e | 80.0% | 84.1% |
| Methacholine PC20 (mg/ml) | ≥ 32 | 81.3% | 71.4% | 85.7% | 93.6%f | 85.7% | 89.8% |
| Gender | Male | 70.2% | 55.9% | 84.0% | 87.4%g | 76.5% | 88.8% |
Note. NS, no statistical significant with a p value > 0.05.
aROC curves were drawn from univariate logistical regression models using DA status (DA+ vs. not) as the dependent variable and the IFN-γ promoter methylation level as the only predictor.
bSensitivity and specificity were calculated from an “optimal cut” that maximized its corresponding average of sensitivity and specificity.
cThe ROC curve was drawn from a multivariate logistical model using DA status (DA+ vs. not) as the dependent variable and the following covariates: the IFN-γ promoter methylation level, DI exposed, smoking status, methacholine PC20 (mg/ml), and gender.
dThe ROC curve was drawn from a multivariate logistical model using DA status (DA+ vs. not) as the dependent variable and the following covariates: the IFN-γ promoter methylation level, smoking status, methacholine PC20 (mg/ml), and gender. The analysis was performed to subjects who had HDI exposure only.
eThe ROC curve was drawn from a multivariate logistical model using DA status (DA+ vs. not) as the dependent variable and the following covariates: the IFN-γ promoter methylation level, DI exposed, methacholine PC20 (mg/ml), and gender. The analysis was performed to nonsmokers only.
fThe ROC curve was drawn from a multivariate logistical model using DA status (DA+ vs. not) as the dependent variable and the following covariates: the IFN-γ promoter methylation level, DI exposed, smoking status, and gender. The analysis was performed to subjects whose methacholine PC20 ≥ 32mg/ml only.
gThe ROC curve was drawn from a multivariate logistical model using DA status (DA+ vs. not) as the dependent variable and the following covariates: the IFN-γ promoter methylation level, DI exposed, smoking status, and methacholine PC20 (mg/ml). The analysis was performed to male workers only.