TABLE 1.
Population Statistics and HER2 Binomial Regression for Entire Cohort.
| NCDB variable | Population statistics | HER2: low vs. negative Binomial | ||
|---|---|---|---|---|
| N | % | Odds Ratio (95% CI) | p Value | |
| HER2‐low | 17,771 | 72.1% | _ | _ |
| ER positivity | 20,161 | 81.8% | 2.13 (1.99–2.30) | <0.001 |
| Age at diagnosis [years] | Continuous | _ | 1.00 (1.00–1.01) | 0.102 |
| Charlson‐Deyo score of 0 | 20,423 | 82.9% | _ | _ |
| Charlson‐Deyo score of 1 | 3172 | 12.9% | 1.03 (0.79–1.33) | 0.853 |
| Charlson‐Deyo score of 2 | 742 | 3.0% | 0.88 (0.67–1.16) | 0.368 |
| Charlson‐Deyo score of 3 | 299 | 1.2% | 1.03 (0.76–1.40) | 0.847 |
| Left breast | 11,731 | 47.6% | 0.99 (0.83–1.17) | 0.884 |
| Right breast | 12,112 | 49.2% | 0.97 (0.82–1.15) | 0.738 |
| Systemic therapy | 20,703 | 84.0% | 0.98 (0.90–1.07) | 0.639 |
| Year of diagnosis 2008–2011 vs 2012–2015 | 20,122 | 81.7% | 1.03 (0.95–1.10) | 0.509 |
| N Stage 0 | 6570 | 26.7% | _ | _ |
| N Stage 1 | 7593 | 30.8% | 0.90 (0.83–0.98) | 0.016 |
| N Stage 2 | 2065 | 8.4% | 0.99 (0.90–1.08) | 0.787 |
| N Stage 3 | 2195 | 8.9% | 1.01 (0.89–1.15) | 0.830 |
| N Stage unknown | 6213 | 25.2% | 1.07 (0.95–1.22) | 0.271 |
| T Stage 0 | 424 | 1.7% | _ | _ |
| T Stage 1 | 3231 | 13.1% | 0.80 (0.64–1.00) | 0.048 |
| T Stage 2 | 5552 | 22.5% | 1.12 (1.01–1.24) | 0.029 |
| T Stage 3 | 2579 | 10.5% | 1.12 (1.03–1.23) | 0.012 |
| T Stage 4 | 5597 | 22.7% | 1.13 (1.00–1.26) | 0.043 |
| T Stage unknown | 7253 | 29.4% | 1.19 (1.08–1.31) | 0.001 |
| Received chemo treatment | 10,957 | 44.5% | 0.92 (0.86–0.97) | 0.002 |
| Distance of patient residence—reporting Hospital [miles] | Continuous | _ | 1.00 (1.00–1.00) | 0.801 |
| Community facility | 2474 | 10.0% | _ | _ |
| Comprehensive community facility | 10,298 | 41.8% | 0.91 (0.81–1.01) | 0.078 |
| Academic facility | 7975 | 32.4% | 0.75 (0.64–0.85) | <0.001 |
| Integrated network facility | 2607 | 10.6% | 0.81 (0.69–0.94) | 0.001 |
| Metropolitan area | 20,753 | 84.2% | _ | _ |
| Urban/suburban area | 2773 | 11.3% | 0.82 (0.68–0.99) | 0.041 |
| Rural area | 398 | 1.6% | 0.84 (0.68–1.03) | 0.096 |
| Female | 24,291 | 98.6% | 1.53 (1.16–2.01) | 0.003 |
| No insurance | 1269 | 5.2% | _ | _ |
| Private insurance | 10,081 | 40.9% | 1.08 (0.84–1.39) | 0.530 |
| Medicaid | 2696 | 10.9% | 1.01 (0.81–1.26) | 0.924 |
| Medicare | 9971 | 40.5% | 1.06 (0.85–1.32) | 0.605 |
| Identify as Hispanic | 2430 | 9.9% | 1.13 (1.03–1.24) | 0.013 |
| Identify Race as White | 19,265 | 78.2% | 0.90 (0.79–1.03) | 0.116 |
| Identify Race as Black | 4141 | 16.8% | 0.97 (0.83–1.13) | 0.685 |
| Median regional household income < $38,000 | 4441 | 18.0% | _ | _ |
| Median regional household income $38,000—$47,999 | 5347 | 21.7% | 1.01 (0.92–1.10) | 0.883 |
| Median regional household income $48,000—$62,999 | 6565 | 26.6% | 1.05 (0.97–1.14) | 0.219 |
| Median regional household income ≤ $63,000 | 8156 | 33.1% | 0.99 (0.91–1.07) | 0.807 |
| Regional high school dropout rate: ≤ 7% | 5955 | 24.2% | _ | _ |
| Regional high school dropout rate: 7%—12.9% | 7882 | 32.0% | 1.01 (0.93–1.09) | 0.894 |
| Regional high school dropout rate: 13%—20.9% | 6244 | 25.3% | 0.94 (0.85–1.03) | 0.189 |
| Regional high school dropout rate: ≥21% | 4442 | 18.0% | 0.86 (0.77–0.97) | 0.015 |