Table 2. Multivariable Analysis With Cox Proportional Hazard Model Adjusted for Covariates to Estimate the Risk of Overall Mortality.
| Covariate | Adjusted Hazard Ratio (95% CI) | P |
|---|---|---|
| Time to treatment initiation, days | < .001 | |
| 0-30 | Reference | |
| 31-60 | 0.99 (0.96 to 1.02) | .584 |
| 61-90 | 1.08 (1.03 to 1.13) | .001 |
| ≥ 91 | 1.23 (1.15 to 1.32) | < .001 |
|
| ||
| Age, years | < .001 | |
| ≤ 30 | 0.37 (0.29 to 0.47) | < .001 |
| 31-40 | 0.36 (0.33 to 0.41) | < .001 |
| 41-50 | 0.45 (0.43 to 0.47) | < .001 |
| 51-60 | 0.53 (0.51 to 0.55) | < .001 |
| 61-70 | 0.65 (0.62 to 0.67) | < .001 |
| > 70 | Reference | |
|
| ||
| Sex | ||
| Male | 1.01 (0.98 to 1.04) | .448 |
| Female | Reference | |
|
| ||
| Race | < .001 | |
| White | Reference | |
| African American | 1.14 (1.09 to 1.18) | < .001 |
| Asian | 0.87 (0.77 to 0.99) | .025 |
| Other | 0.87 (0.79 to 0.97) | .009 |
|
| ||
| Hispanic ethnicity | < .001 | |
| Non-Hispanic | Reference | |
| Hispanic | 0.87 (0.81 to 0.94) | < .001 |
| Other | 0.99 (0.95 to 1.04) | .876 |
|
| ||
| Insurance status | < .001 | |
| Private insurance | Reference | |
| Medicare | 1.47 (1.42 to 1.52) | < .001 |
| Medicaid | 1.86 (1.78 to 1.95) | < .001 |
| Uninsured | 1.58 (1.49 to 1.67) | < .001 |
| Other government | 1.57 (1.43 to 1.72) | < .001 |
|
| ||
| Facility type | .011 | |
| Community | Reference | |
| Comprehensive community | 0.96 (0.92 to 1.00) | .038 |
| Academic | 0.97 (0.92 to 1.01) | .128 |
| Other | 1.15 (1.01 to 1.31) | .044 |
|
| ||
| Transition to academic facility | < .001 | |
| Yes | 0.91 (0.88 to 0.95) | < .001 |
| No | Reference | |
|
| ||
| Cancer primary site | < .001 | |
| Oropharynx, tonsil | Reference | |
| Oropharynx, nontonsil | 1.74 (1.64 to 1.86) | < .001 |
| Oral tongue | 1.39 (1.33 to 1.39) | < .001 |
| Larynx | 1.37 (1.32 to 1.43) | < .001 |
| Hypopharynx | 2.04 (1.94 to 2.15) | < .001 |
|
| ||
| Overall AJCC stage group | < .001 | |
| I | Reference | |
| II | 1.61 (1.59 to 1.64) | < .001 |
| II | 1.97 (1.95 to 1.99) | < .001 |
| IV | 2.63 (2.61 to 2.64) | < .001 |
|
| ||
| Treatment | < .001 | |
| Surgery alone | Reference | |
| RT alone | 1.19 (1.14 to 1.23) | < .001 |
| CRT | 0.93 (0.91 to 0.98) | .001 |
| Adjuvant RT | 0.83 (0.78 to 0.87) | < .001 |
| Adjuvant CRT | 0.75 (0.71 to 0.80) | < .001 |
| Adjuvant chemotherapy | 1.30 (1.09 to 1.55) | .001 |
| Preoperative RT | 1.34 (1.13 to 1.58) | .001 |
| Preoperative CRT | 0.94 (0.85 to 1.05) | .277 |
| Induction chemotherapy | 1.25 (0.93 to 1.68) | .144 |
|
| ||
| Treatment year | .432 | |
| 2003 | 1.02 (0.99 to 1.05) | .203 |
| 2004 | 1.01 (0.98 to 1.04) | .636 |
| 2005 | Reference | |
|
| ||
| Charlson/Deyo comorbidity score | < .001 | |
| 0 | Reference | |
| 1 | 1.34 (1.29 to 1.38) | < .001 |
| ≥ 2 | 1.76 (1.66 to 1.85) | < .001 |
|
| ||
| Zip-code level education, % | < .001 | |
| ≥ 29 | 1.14 (1.09 to 1.20) | < .001 |
| 20-28.9 | 1.09 (1.05 to 1.14) | < .001 |
| 14-19.9 | 1.05 (1.01 to 1.09) | < .001 |
| < 14 | Reference | |
| Unknown | 1.74 (0.24 to 12.36) | .581 |
|
| ||
| Zip-code level income, $ | < .001 | |
| < 30,000 | 1.14 (1.09 to 1.20) | < .001 |
| 30,000-35,000 | 1.11 (1.06 to 1.15) | < .001 |
| 35,000-45,999 | 1.05 (1.01 to 1.09) | .018 |
| ≥ 46,000 | Reference | |
| Unknown | 0.62 (0.09 to 4.44) | .636 |
|
| ||
| Distance from treatment facility, miles | < .001 | |
| ≥ 10 | Reference | |
| 11-20 | 0.95 (0.92 to 0.98) | .004 |
| 21-50 | 0.93 (0.90 to 0.96) | < .001 |
| 51-100 | 0.87 (0.83 to 0.92) | < .001 |
| > 100 | 0.78 (0.73 to 0.84) | < .001 |
Abbreviations: AJCC, American Joint Committee on Cancer; CRT, chemoradiation; RT, radiation therapy.