TABLE II.
Multivariable Cox Regression Hazards Model Evaluating the Association Between Covariates and the Risk of Overall Mortality
| Covariate | Adjusted HR* | P Value |
|---|---|---|
| Age | ||
| <18 years | Reference | |
| ≥18 years | 1.88 (1.68 to 2.11) | <0.001 |
| Sex | ||
| Male | Reference | |
| Female | 0.87 (0.81 to 0.93) | <0.001 |
| Race or ethnicity | ||
| White | Reference | |
| Hispanic | 0.89 (0.78 to 1.00) | 0.059 |
| Black | 0.80 (0.69 to 0.93) | 0.004 |
| Asian | 0.83 (0.65 to 1.06) | 0.130 |
| Other | 0.97 (0.76 to 1.25) | 0.832 |
| Modified Charlson-Deyo Comorbidity Index score | ||
| 0 | Reference | |
| 1 | 1.14 (1.03 to 1.27) | 0.013 |
| ≥2 | 1.63 (1.39 to 1.90) | <0.001 |
| Tumor stage | ||
| I | Reference | |
| II | 2.61 (2.36 to 2.89) | <0.001 |
| III | 3.27 (2.63 to 4.07) | <0.001 |
| IV | 8.43 (7.58 to 9.37) | <0.001 |
| Diagnosis | ||
| Osteosarcoma | Reference | |
| Ewing sarcoma or primitive neuroectodermal tumor | 0.76 (0.68 to 0.86) | <0.001 |
| Chondrosarcoma | 0.70 (0.63 to 0.78) | <0.001 |
| Others | 0.89 (0.80 to 0.98) | 0.021 |
| Facility type | ||
| Academic or research | Reference | |
| Not academic or research | 1.00 (0.91 to 1.10) | 0.981 |
| Facility volume | ||
| Low | Reference | |
| Medium | 0.71 (0.64 to 0.79) | <0.001 |
| High | 0.72 (0.66 to 0.80) | <0.001 |
| Insurance status | ||
| Private | Reference | |
| Medicare | 2.71 (2.48 to 2.97) | <0.001 |
| Medicaid | 1.20 (1.07 to 1.35) | 0.002 |
| Other government | 1.06 (0.80 to 1.40) | 0.676 |
| Uninsured | 1.03 (0.86 to 1.23) | 0.768 |
| ZIP Code-level income | ||
| <$38,000 | Reference | |
| $38,000 to $47,999 | 1.00 (0.89 to 1.12) | 0.927 |
| $48,000 to $63,000 | 0.89 (0.79 to 1.01) | 0.079 |
| >$63,000 | 0.89 (0.77 to 1.03) | 0.110 |
| ZIP Code-level lack of high-school education | ||
| <7.0% | Reference | |
| 7.0% to 20.9% | 0.96 (0.87 to 1.07) | 0.447 |
| ≥21.0% | 0.90 (0.77 to 1.04) | 0.146 |
| Rurality | ||
| Rural | Reference | |
| Suburban | 1.05 (0.95 to 1.17) | 0.337 |
| Metropolitan | 0.96 (0.74 to 1.25) | 0.775 |
| Facility location | ||
| Pacific | Reference | |
| Mountain | 1.06 (0.89 to 1.28) | 0.507 |
| West North Central | 1.08 (0.92 to 1.27) | 0.344 |
| East North Central | 0.96 (0.83 to 1.10) | 0.537 |
| Middle Atlantic | 0.87 (0.75 to 1.01) | 0.060 |
| New England | 1.05 (0.86 to 1.29) | 0.615 |
| West South Central | 1.11 (0.94 to 1.31) | 0.215 |
| East South Central | 1.05 (0.88 to 1.24) | 0.593 |
| South Atlantic | 1.02 (0.89 to 1.17) | 0.744 |
*
The values are given as the adjusted HR, with the 95% CI in parentheses.