Table 4. Univariable and Multivariable Cox Proportional Hazards Regression Models for Overall Survival.
| Characteristics | Univariable analysis | Multivariable analysis | ||
|---|---|---|---|---|
| HR (95% CI) | P value | HR (95% CI) | P value | |
| MSI testing | ||||
| No | 1 [Reference] | NA | 1 [Reference] | NA |
| Yes | 0.62 (0.60-0.63) | <.001 | 0.93 (0.91-0.96) | <.001 |
| KRAS testing | ||||
| No | 1 [Reference] | NA | 1 [Reference] | NA |
| Yes | 0.71 (0.69-0.72) | <.001 | 0.97 (0.95-1.00) | .03 |
| Age, y | ||||
| 18-49 | 1 [Reference] | NA | 1 [Reference] | NA |
| 50-59 | 1.16 (1.12-1.20) | <.001 | 1.06 (1.02-1.10) | .007 |
| 60-69 | 1.43 (1.38-1.49) | <.001 | 1.16 (1.12-1.21) | <.001 |
| 70-79 | 1.90 (1.83-1.97) | <.001 | 1.30 (1.24-1.35) | <.001 |
| Sex | ||||
| Male | 1 [Reference] | NA | 1 [Reference] | NA |
| Female | 0.96 (0.94-0.98) | <.001 | 0.98 (0.96-1.00) | .07 |
| Ethnicitya | ||||
| Non-Hispanic | 1 [Reference] | NA | 1 [Reference] | NA |
| Hispanic | 0.83 (0.79-0.87) | <.001 | 0.84 (0.79-0.88) | <.001 |
| CCI | ||||
| 0 | 1 [Reference] | NA | 1 [Reference] | NA |
| 1 | 1.18 (1.15-1.21) | <.001 | 1.08 (1.05-1.11) | <.001 |
| ≥2 | 1.60 (1.54-1.66) | <.001 | 1.28 (1.24-1.34) | <.001 |
| Grade | ||||
| Well-differentiated | 1 [Reference] | NA | 1 [Reference] | NA |
| Moderately differentiated | 1.03 (0.97-1.08) | .40 | 1.12 (1.06-1.18) | <.001 |
| Poorly differentiated | 1.59 (1.50-1.69) | <.001 | 1.80 (1.70-1.91) | <.001 |
| Insurance type | ||||
| Private | 1 [Reference] | NA | 1 [Reference] | NA |
| No insurance | 1.38 (1.31-1.45) | <.001 | 1.20 (1.14-1.26) | <.001 |
| Medicaid | 1.26 (1.21-1.31) | <.001 | 1.14 (1.09-1.18) | <.001 |
| Medicare or otherb | 1.56 (1.52-1.60) | <.001 | 1.13 (1.10-1.16) | <.001 |
| Unknown | 1.32 (1.19-1.47) | <.001 | 1.08 (0.98-1.20) | .14 |
| Educational level in area of residence, %c | ||||
| ≥17.6 | 1 [Reference] | NA | 1 [Reference] | NA |
| 10.9-17.5 | 1.03 (1.00-1.06) | .11 | 0.99 (0.96-1.03) | .62 |
| 6.3-10.8 | 0.97 (0.94-1.00) | .02 | 0.98 (0.94-1.02) | .29 |
| Unknown | 1.02 (0.91-1.15) | .69 | 1.06 (0.69-1.62) | .78 |
| Facility type with CP | ||||
| Academic | 1 [Reference] | NA | 1 [Reference] | NA |
| Community | 1.24 (1.19-1.29) | <.001 | 1.07 (1.02-1.12) | .003 |
| Comprehensive | 1.20 (1.17-1.23) | <.001 | 1.13 (1.10-1.17) | <.001 |
| Integrated network | 1.16 (1.13-1.20) | <.001 | 1.13 (1.09-1.16) | <.001 |
| Median household income, US$ | ||||
| ≥63 333 | 1 [Reference] | NA | 1 [Reference] | NA |
| 50 354-63 332 | 1.09 (1.06-1.12) | <.001 | 1.05 (1.01-1.08) | .007 |
| 40 227-50 353 | 1.16 (1.12-1.19) | <.001 | 1.08 (1.04-1.12) | <.001 |
| <40 277 | 1.20 (1.17-1.24) | <.001 | 1.10 (1.05-1.15) | <.001 |
| Unknown | 1.13 (1.01-1.26) | .04 | 0.97 (0.65-1.46) | .89 |
| Year of diagnosis | ||||
| 2010 | 1 [Reference] | NA | 1 [Reference] | NA |
| 2011 | 0.96 (0.92-1.00) | .07 | 0.97 (0.93-1.01) | .18 |
| 2012 | 0.93 (0.89-0.97) | <.001 | 0.92 (0.88-0.96) | <.001 |
| 2013 | 0.95 (0.91-0.99) | .01 | 0.96 (0.92-1.00) | .07 |
| 2014 | 0.96 (0.92-1.00) | .05 | 0.98 (0.94-1.02) | .31 |
| 2015 | 0.91 (0.87-0.95) | <.001 | 0.93 (0.89-0.97) | .002 |
| 2016 | 0.86 (0.82-0.90) | <.001 | 0.91 (0.87-0.95) | <.001 |
| 2017 | 0.81 (0.77-0.85) | <.001 | 0.83 (0.79-0.87) | <.001 |
| Immunotherapy | ||||
| Not administered | 1 [Reference] | NA | 1 [Reference] | NA |
| Administered | 0.65 (0.63-0.67) | <.001 | 0.85 (0.82-0.87) | <.001 |
| Unknown | 0.85 (0.68-1.05) | .13 | 0.97 (0.77-1.21) | .76 |
| Chemotherapy | ||||
| Not administered | 1 [Reference] | NA | 1 [Reference] | NA |
| Administered | 0.31 (0.30-0.32) | <.001 | 0.37 (0.36-0.38) | <.001 |
| Unknown | 0.41 (0.38-0.44) | <.001 | 0.49 (0.45-0.52) | <.001 |
| Lung metastasis at presentation | ||||
| Absent | 1 [Reference] | NA | 1 [ Reference] | NA |
| Present | 1.33 (1.30-1.37) | <.001 | 1.16 (1.13-1.19) | <.001 |
| Unknown | 1.51 (1.39-1.64) | <.001 | 1.07 (0.98-1.17) | .14 |
| Liver metastasis at presentation | ||||
| Absent | 1 [Reference] | NA | 1 [Reference] | NA |
| Present | 1.10 (1.07-1.13) | <.001 | 1.27 (1.23-1.30) | <.001 |
| Unknown | 1.52 (1.33-1.73) | <.001 | 1.09 (0.95-1.26) | .21 |
| Surgery primary site | ||||
| No | 1 [Reference] | NA | 1 [Reference] | NA |
| Yes | 0.46 (0.45-0.47) | <.001 | 0.53 (0.52-0.55) | <.001 |
| Unknown | 0.54 (0.39-0.74) | <.001 | 0.58 (0.42-0.82) | .002 |
| Surgery nonprimary site | ||||
| No | 1 [Reference] | NA | 1 [Reference] | NA |
| Yes | 0.56 (0.54-0.58) | <.001 | 0.81 (0.79-0.84) | <.001 |
| Unknown | 0.56 (0.38-0.83) | .003 | 0.78 (0.53-1.15) | .21 |
| Area of residence | ||||
| Metropolitan | 1 [Reference] | NA | 1 [Reference] | NA |
| Urban | 1.11 (1.08-1.15) | <.001 | 1.04 (1.00-1.08) | .07 |
| Rural | 1.16 (1.06-1.26) | .001 | 1.11 (1.02-1.22) | .02 |
| Facility locationd | ||||
| New England | 1 [Reference] | NA | 1 [Reference] | NA |
| Middle Atlantic | 0.91 (0.86-0.96) | .001 | 0.85 (0.80-0.90) | <.001 |
| South Atlantic | 1.03 (0.98-1.09) | .28 | 1.02 (0.96-1.08) | .56 |
| East North Central | 1.08 (1.02-1.14) | .01 | 1.08 (1.02-1.14) | .008 |
| East South Central | 1.07 (1.00-1.15) | .04 | 1.03 (0.97-1.11) | .35 |
| West North Central | 1.03 (0.97-1.10) | .35 | 1.06 (1.00-1.13) | .07 |
| West South Central | 0.96 (0.90-1.02) | .21 | 0.84 (0.79-0.89) | <.001 |
| Mountain | 1.01 (0.94-1.09) | .73 | 0.94 (0.87-1.00) | .07 |
| Pacific | 0.98 (0.93-1.04) | .50 | 0.98 (0.92-1.04) | .45 |
| Travel distance, miles | ||||
| ≤5 | 1 [Reference] | NA | 1 [Reference] | NA |
| 5.1-10 | 0.94 (0.92-0.97) | <.001 | 0.98 (0.95-1.01) | .22 |
| 10.1-25 | 0.90 (0.87-0.93) | <.001 | 0.99 (0.97-1.03) | .75 |
| >25 | 0.90 (0.87-0.93) | <.001 | 0.99 (0.96-1.03) | .71 |
Abbreviations: CCI, Charlson Comorbidity Index (range: 0-25, with the highest score indicating a higher number of comorbidities); CP, cancer program; HR, hazard ratio; MSI, microsatellite instability; NA, not applicable.
a
Ethnicity data obtained from the NCDB were self-identified in the patients’ medical records. Hispanic ethnicity includes Mexican, Puerto Rican, Cuban, South or Central American (except Brazil), Dominican Republic, or Spanish origin.
b
Other insurance type includes other governmental insurance.
c
Educational level was assessed at the zip code level based on the percentage of adult residents without a high school diploma.
d
US Census division.