Table 2. Multivariable Analysis for Epidemiological and Demographic Factors Associated With ERBB2-Low Statusa.
| Variable | ERBB2-low status, aOR (95% CI) | P value |
|---|---|---|
| Age, per 10 y | 0.98 (0.98-0.98) | <.001 |
| Sex | ||
| Female | 1 [Reference] | NA |
| Male | 1.00 (0.98-1.03) | .68 |
| Charlson-Deyo Comorbidity Index | ||
| 0 | 1 [Reference] | NA |
| ≥1 | 1.01 (1.00-1.01) | .14 |
| Facility type | ||
| Community cancer program | 1 [Reference] | NA |
| Comprehensive community cancer program | 1.07 (1.05-1.09) | <.001 |
| Academic or research | 0.83 (0.81-0.84) | <.001 |
| Integrated network cancer program | 1.04 (1.02-1.06) | <.001 |
| Receptor, per 10% expression | ||
| Estrogen | 1.15 (1.15-1.15) | <.001 |
| Progesterone | 0.95 (0.95-0.95) | <.001 |
| Race and ethnicity | ||
| Asian or Pacific Islander | 1.02 (0.99-1.04) | .15 |
| Hispanic | 0.85 (0.83-0.86) | <.001 |
| Native American | 1.22 (1.13-1.32) | <.001 |
| Non-Hispanic Black | 1.01 (1.00-1.03) | .06 |
| Non-Hispanic White | 1 [Reference] | NA |
| Otherb | 0.84 (0.80-0.89) | <.001 |
| Stage | ||
| I | 1 [Reference] | NA |
| II | 1.11 (1.10-1.12) | <.001 |
| III | 1.12 (1.11-1.14) | <.001 |
| IV | 1.00 (0.98-1.02) | .91 |
| Grade | ||
| 1 | 1 [Reference] | NA |
| 2 | 1.02 (1.01-1.03) | <.001 |
| 3 | 1.04 (1.03-1.06) | <.001 |
| Tumor histology | ||
| Ductal | 1 [Reference] | NA |
| Lobular | 0.73 (0.72-0.74) | <.001 |
| Ductal and lobular | 0.85 (0.84-0.87) | <.001 |
| Mucinous | 0.51 (0.49-0.52) | <.001 |
| Papillary | 0.95 (0.88-1.03) | .23 |
| Tubular | 0.99 (0.94-1.05) | .75 |
| Inflammatory | 1.00 (0.91-1.11) | .99 |
| Medullary | 0.94 (0.85-1.04) | .25 |
| Metaplastic | 0.53 (0.50-0.56) | <.001 |
| Paget disease | 1.24 (1.04-1.48) | .02 |
| Sarcoma | 0.5 (0.38-0.67) | <.001 |
| Other | 0.85 (0.82-0.87) | <.001 |
Abbreviations: aOR, adjusted odds ratio; ERBB2, erb-b2 receptor tyrosine kinase 2; NA, not applicable.
a
Analysis performed with logistic regression in all 1 136 016 patients, with imputation for missing values.
b
Other is a subcategory listed in the National Cancer Database (NCDB) and represents patients who were coded as such by the local cancer registry. No explicitly defined racial or ethnic subgroup categorized by the NCDB was collapsed into this category.