Table 4.
The features selected with forward stepwise feature selection of SVM model and logistic regression for three AHI cutoffs
| Method | Order | AHI ≥ 5/h | AHI ≥ 15/h | AHI ≥ 30/h |
|---|---|---|---|---|
| SVM | 1 | Waist circumference | Waist circumference | Waist circumference |
| 2 | Age | Age | Witnessed apnea | |
| 3 | Neck circumference | Age | ||
| 4 | Snoring | Neck circumference | ||
| 5 | Witnessed apnea | Snoring | ||
| 6 | SOL < 30 min | SOL < 30 min | ||
| Logistic regression | N/A | Snoring | Snoring | Witnessed apnea |
| Gender | Witnessed apnea | Gender | ||
| Age | Dry throat | Snoring | ||
| Neck circumference | Gender | Hypertension | ||
| SOL | Hypnotic | Dry throat | ||
| BMI | Age | Waist circumference | ||
| Waist circumference | Waist circumference | Age | ||
| Neck circumference | Neck circumference | |||
| SOL | BMI | |||
| BMI | SOL |
In SVM model, the minimal feature set was selected to achieve the target criteria in the AUROC. When AHI cutoffs were 5/h and 15/h, the target AUROC was set as 0.8. While AHI cutoff was 30/h, the experiment showed that the maximum AUROC was 0.78, so we selected minimum features to achieve the performance. N/A, not applicable.