Table 2. Multivariable Cox Regression for All-Cause Mortality.
| Variable | Hazard Ratio (95% CI)a |
|---|---|
| TS-RT, d | |
| ≤42 | 1 [Reference] |
| 43-49 | 0.98 (0.93-1.04) |
| ≥50 | 1.07 (1.02-1.12) |
| Sex | |
| Male | 1 [Reference] |
| Female | 0.90 (0.86-0.94) |
| Age, y | |
| ≤50 | 1 [Reference] |
| 51-60 | 1.20 (1.13-1.28) |
| 61-70 | 1.29 (1.20-1.38) |
| ≥71 | 1.76 (1.62-1.91) |
| Race | |
| White | 1 [Reference] |
| Black | 1.03 (0.96-1.10) |
| Other | 0.98 (0.88-1.10) |
| Educationb | |
| ≥21% | 1.06 (0.97-1.15) |
| 13%-20.9% | 1.07 (0.99-1.15) |
| 7%-12.9% | 1.05 (0.98-1.12) |
| <7% | 1 [Reference] |
| Unknown | 1.78 (0.44-7.19) |
| Income, $c | |
| <38,000 | 1.18 (1.09-1.28) |
| 38 000-47 999 | 1.09 (1.02-1.17) |
| 48 000-62 999 | 1.06 (1.00-1.13) |
| ≥63 000 | 1 [Reference] |
| Unknown | 1.07 (0.27-4.29) |
| Insurance | |
| Medicare | 1 [Reference] |
| Medicaid | 1.02 (0.95-1.10) |
| Private/managed care/other government | 0.73 (0.69-0.77) |
| None | 0.90 (0.82-0.99) |
| Unknown | 0.85 (0.71-1.01) |
| Charlson/Deyo score | |
| 0 | 1 [Reference] |
| 1 | 1.11 (1.05-1.17) |
| ≥2 | 1.52 (1.40-1.66) |
| Disease site | |
| Tonsil | 0.44 (0.41-0.49) |
| Nontonsil oropharynx | 1 [Reference] |
| Oral cavity | 1.91 (1.77-2.05) |
| Larynx | 1.53 (1.41-1.66) |
| Hypopharynx | 1.62 (1.45-1.82) |
| Stage | |
| III | 1 [Reference] |
| IV | 1.26 (1.20-1.33) |
| Extracapsular extension | |
| No | 1 [Reference] |
| Yes | 1.39 (1.32-1.46) |
| Node negative | 0.75 (0.71-0.79) |
| Unknown | 1.02 (0.94-1.10) |
| Margin status | |
| Negative | 1 [Reference] |
| Positive | 1.36 (1.27-1.46) |
| Unknown | 1.25 (1.18-1.32) |
| Lymphovascular invasion | |
| Absent | 1 [Reference] |
| Present | 1.36 (1.26-1.47) |
| Unknown | 1.02 (0.93-1.13) |
| Year of diagnosis | |
| 2004-2006 | 1 [Reference] |
| 2007-2009 | 0.92 (0.88-0.98) |
| 2010-2013 | 0.84 (0.76-0.92) |
| TD-S, d | |
| <68 | 1 [Reference] |
| ≥68 | 1.02 (0.95-1.10) |
| Treating facilities | |
| Academic (surgery and radiation) | 1 [Reference] |
| Academic (surgery) | 1.11 (1.04-1.19) |
| Comprehensive community (surgery and radiation) | 1.06 (1.01-1.12) |
| Comprehensive community (surgery) | 1.06 (0.97-1.17) |
| Community (surgery and radiation) | 1.06 (0.96-1.16) |
| Community (surgery) | 1.16 (0.98-1.37) |
| Other (surgery and radiation) | 0.99 (0.91-1.07) |
| Other (surgery) | 1.07 (0.94-1.22) |
| Distance to facility, mile | |
| ≤10 | 1 [Reference] |
| 11-20 | 0.96 (0.90-1.01) |
| 21-50 | 0.93 (0.88-0.98) |
| 51-100 | 0.87 (0.80-0.94) |
| >100 | 0.87 (0.79-0.95) |
| Hospital length of stay, d | |
| 0-7 | 1 [Reference] |
| >7 | 1.24 (1.18-1.30) |
| Unknown | 1.11 (1.05-1.17) |
| 30-Day unplanned readmission status | |
| No | 1 [Reference] |
| Yes | 1.06 (0.95-1.18) |
| Unknown | 1.06 (0.97-1.16) |
| Radiation dose, Gy | |
| 45.00-49.99 | 1.68 (1.43-1.97) |
| 50.00-53.99 | 1.16 (1.04-1.28) |
| 54.00-59.99 | 1.13 (1.05-1.21) |
| 60.00-65.99 | 1 [Reference] |
| 66.00-69.99 | 1.08 (1.02-1.13) |
| 70.00-76.00 | 1.26 (1.18-1.34) |
| Radiation modality | |
| 3-D Conformal | 1 [Reference] |
| IMRT | 0.92 (0.82-1.03) |
| Unknown | 0.94 (0.83-1.05) |
| Chemotherapy | |
| Not given | 1.10 (1.05-1.15) |
| Adjuvant | 1 [Reference] |
| Neoadjuvant | 1.16 (0.97-1.39) |
| Adjuvant and neoadjuvant | 1.02 (0.80-1.31) |
| Unknown | 0.86 (0.73-1.01) |
Abbreviations: 3-D, 3-dimensional; IMRT, intensity modulated radiation therapy; TD-S, time from diagnosis to surgery; TS-RT, time from surgery to radiation.
a
Multivariable model included TS-RT, sex, age, race, education, income, insurance type, Charlson/Deyo score, disease site, stage, extracapsular extension, margin status, lymphovascular invasion, year of diagnosis, TD-S, facility type, distance to facility, hospital length of stay, readmission status, radiation dose, radiation modality, and chemotherapy use.
b
Education indicates the percent of people with no high school degree in the patient’s zip code of residence.
c
Income indicates the median household income in the patient’s zip code of residence.