Table 4.
Final Model From Two Block Backwards Stepwise (Conditional) Multivariable Cox Regression Analysis for Predictors of the Primary Composite End Point of the Sleep Apnea Cardioascular Endpoints (SAVE) Study Outcome at 2 Years
| Variable | Hazard Ratio (95% CI) | Hazard Ratio, Z-Normalized Value for Scale Variables (95% CI) | P Value |
|---|---|---|---|
| Diabetes mellitus | 1.50 (1.23-1.83) | … | < .001 |
| Ethnicity (simplified) | |||
| White/European | Reference | … | .092 |
| Asian | 1.23 (0.95-1.59) | … | .111 |
| Other | 0.85 (0.56-1.28) | … | .436 |
| Hypertension | 1.43 (1.10-1.86) | … | .008 |
| Cardiovascular disease history | |||
| Cardiac only | Reference | … | < .001 |
| Cerebrovascular only | 0.78 (0.63-0.97) | … | .028 |
| Both | 2.74 (1.98-3.79) | … | < .001 |
| Age at baseline | 1.01 (1.00-1.02) | 1.07 (0.97-1.18) | .167 |
| Waist:hip ratio | 5.73 (1.69-19.45) | 1.15 (1.04-1.26) | .005 |
| Oxygen desaturation index | 1.00 (0.99-1.00) | 0.92 (0.82-1.02) | .125 |
| Median desaturation duration, s | 1.01 (1.00-1.02) | 1.09 (0.99-1.21) | .073 |
Regression formula for the primary composite outcome: 0.003 + 0.405∗1(if diabetic, 0 if not) + 0.209∗1(if Asian, 0 if not) + 0.355∗1(if hypertension, 0 if no) + 1.746∗waist:hip ratio + -0.005∗ODI + 1.008∗1(if both cardiac and cerebrovascular disease history, 0 if not) + 0.009∗median desaturation duration.