Table 2.
Univariate and multivariate Cox proportional hazards model for overall survival
| Parameter (comparator vs reference) | Univariate | Multivariate | ||||
|---|---|---|---|---|---|---|
| HR | 95% CI | P‐value | HR | 95% CI | P‐value | |
| Treatment group (CT alone vs surgery/CRT) | 2.276 | 1.602‐3.235 | <0.001 | 2.824 | 1.711‐4.661 | <0.001 |
| Age (continuous) | 1.013 | 1.002‐1.025 | 0.025 | 1.019 | 1.005‐1.034 | 0.028 |
| Gender (male vs female) | 0.928 | 0.706‐1.220 | 0.592 | |||
| Race (others vs white) | 0.993 | 0.690‐1.430 | 0.971 | |||
| Charlson‐Deyo score (0 vs 2) | 0.582 | 0.362‐0.937 | 0.026 | |||
| Charlson‐Deyo score (1 vs 2) | 0.648 | 0.370‐1.134 | 0.129 | |||
| Distance to treating facility (continuous) | 0.999 | 0.998‐1.001 | 0.390 | |||
| Insurance (private vs uninsured) | 0.806 | 0.403‐1.612 | 0.542 | |||
| Insurance (Medicaid/other government vs uninsured) | 1.336 | 0.608‐2.936 | 0.471 | |||
| Insurance (Medicare vs uninsured) | 1.069 | 0.543‐2.105 | 0.847 | |||
| Income ($30 000‐$34 999 vs <$30 000) | 1.312 | 0.883‐1.949 | 0.179 | |||
| Income ($35 000‐$45 999 vs <$30 000) | 0.966 | 0.649‐1.438 | 0.864 | |||
| Income (≥$46 000 vs <$30 000) | 0.978 | 0.652‐1.465 | 0.912 | |||
| Location (urban vs metro) | 1.108 | 0.783‐1.569 | 0.563 | |||
| Location (rural vs metro) | 1.031 | 0.423‐2.514 | 0.947 | |||
| Percentage of adults in zip code without high school diploma (13‐20.9% vs ≥21%) | 0.788 | 0.512‐1.211 | 0.277 | 0.881 | 0.535‐1.450 | 0.618 |
| Percentage of adults in zip code without high school diploma (7‐12.9% vs ≥21%) | 0.968 | 0.658‐1.424 | 0.868 | 0.735 | 0.464‐1.165 | 0.190 |
| Percentage of adults in zip code without high school diploma (<7% vs ≥21%) | 0.715 | 0.494‐1.036 | 0.076 | 0.530 | 0.342‐0.823 | 0.005 |
| Facility type (academic vs community) | 0.698 | 0.537‐0.907 | 0.007 | 0.525 | 0.382‐0.721 | <0.001 |
| Facility location (South vs Northeast) | 1.008 | 0.715‐1.421 | 0.964 | |||
| Facility location (Midwest vs Northeast) | 1.034 | 0.720‐1.486 | 0.855 | |||
| Facility location (West vs Northeast) | 0.894 | 0.587‐1.363 | 0.603 | |||
| T stage (T2 vs T1) | 0.848 | 0.498‐1.444 | 0.544 | |||
| T stage (T3/4 vs T1) | 1.135 | 0.773‐1.667 | 0.518 | |||
| N stage (N1 vs N0) | 1.392 | 1.020‐1.898 | 0.037 | 1.568 | 1.134‐2.167 | 0.007 |
| N stage (N2/3 vs N0) | 2.620 | 1.403‐4.894 | 0.003 | 3.834 | 1.982‐7.418 | <0.001 |
| Year of diagnosis (2009‐2014 vs 2004‐2008) | 0.945 | 0.725‐1.232 | 0.678 | |||
Statistically significant P values are in bold. Only values included in the final multivariate model are shown. CI, confidence interval; HR, hazard ratio.