Table 5.
Generalized regression models for SDQTc, STVQT, and QTVI during desaturations
| Model 1 (Confounding Factors and Comorbidities) | ||||||
|---|---|---|---|---|---|---|
| Predictors | SDQTc |
STVQT |
QTVI |
|||
| β-Coeff | P value | β-Coeff | P value | β-Coeff | P value | |
| Age, yr | −0.008 | 0.259 | 0.016 | <0.01 | 0.007 | <0.01 |
| BMI, kg/m2 | −0.014 | 0.171 | 0.005 | 0.343 | 0.004 | <0.01 |
| Sex (male) | −1.057 | <0.01 | −0.284 | <0.01 | −0.084 | <0.01 |
| AHI, 1/h | 0.005 | 0.139 | −0.003 | 0.045 | −0.001 | <0.01 |
| NREM sleep | 0.968 | <0.01 | 0.356 | <0.01 | 0.060 | 0.028 |
| Arousal | 1.741 | <0.01 | −0.204 | 0.029 | −0.429 | <0.01 |
| Pre-desaturation value, ms | 0.544 | <0.01 | 0.595 | <0.01 | 0.591 | <0.01 |
| Desaturation duration, s | 0.077 | <0.01 | 0.006 | 0.034 | −0.008 | <0.01 |
| Desaturation depth, % | 0.405 | <0.01 | 0.151 | <0.01 | 0.009 | <0.01 |
| COPD | 1.034 | <0.01 | 0.250 | 0.117 | 0.264 | <0.01 |
| Hypothyroidism | 4.216 | <0.01 | 2.046 | <0.01 | 0.397 | <0.01 |
| Hypertension | −0.542 | <0.01 | 0.051 | 0.585 | 0.053 | 0.023 |
| T2DM | −0.161 | 0.414 | 0.233 | 0.025 | 0.120 | <0.01 |
| Stroke history | 1.844 | <0.01 | 0.327 | 0.116 | 0.157 | <0.01 |
| Model 2 (Confounding Factors and Medications) | ||||||
|---|---|---|---|---|---|---|
| Predictors | SDQTc |
STVQT |
QTVI |
|||
| β-Coeff | P value | β-Coeff | P value | β-Coeff | P value | |
| Age, yr | 0.063 | <0.01 | 0.038 | <0.01 | 0.001 | <0.01 |
| BMI, kg/m2 | 0.060 | <0.01 | 0.028 | <0.01 | −0.004 | <0.01 |
| Sex (male) | −0.601 | <0.01 | −0.323 | <0.01 | −0.117 | <0.01 |
| AHI, 1/h | 0.005 | 0.108 | −0.008 | <0.01 | −0.001 | <0.01 |
| NREM sleep | 1.135 | <0.01 | 0.357 | <0.01 | 0.022 | 0.411 |
| Arousal | 2.411 | <0.01 | 0.054 | 0.566 | −0.404 | <0.01 |
| Pre-desaturation value, ms | 0.527 | <0.01 | 0.590 | <0.01 | 0.612 | <0.01 |
| Desaturation duration, s | 0.075 | <0.01 | 0.004 | 0.144 | −0.012 | <0.01 |
| Desaturation depth, % | 0.287 | <0.01 | 0.101 | <0.01 | 0.01 | <0.01 |
| Antipsychotic | 3.024 | <0.01 | 1.885 | <0.01 | 0.250 | <0.01 |
| β-blockers | −1.797 | <0.01 | −0.101 | 0.371 | 0.281 | <0.01 |
| Calcium blockers | 1.369 | <0.01 | 0.691 | <0.01 | 0.175 | <0.01 |
Parameters except desaturation duration, desaturation depth, and pre-desaturation values are treated patient wise; these parameters were computed for each desaturation separately. Boldface values indicate statistical significance (P < 0.01). AHI, apnea-hypopnea index; BMI, body mass index; β-Coeff, β-coefficient; COPD, chronic obstructive pulmonary disease; SDQTc, standard deviation of QTc, NREM, nonrapid eye movement; QTVI, QT variability index; STVQT, short-time variability of QT; T2DM, diabetes mellitus type II.