Table 2. Multivariable Logistic Regression for the Presence of Brain Metastases at Diagnosis of Breast Cancera.
| Variable | Patients, No. | Among Entire Cohort | Among Subset With Metastatic Disease | |||
|---|---|---|---|---|---|---|
| Patients (n = 238 726) |
With Brain Metastases (n = 968) |
OR (95% CI) | P Value | OR (95% CI) | P Value | |
| Age at diagnosis, yb | ||||||
| 18-40 | 13 564 | 57 | 1 [Reference] | NA | 1 [Reference] | NA |
| 41-60 | 98 184 | 423 | NA | NA | 1.41 (1.05-1.88) | .02 |
| 61-80 | 103 700 | 425 | NA | NA | 1.40 (1.04-1.88) | .03 |
| >80 | 23 265 | 63 | NA | NA | NA | NA |
| Sex | ||||||
| Male | 1854 | 10 | 1 [Reference] | NA | 1 [Reference] | NA |
| Female | 236 872 | 958 | NA | NA | NA | NA |
| Raceb | ||||||
| White | 165 808 | 603 | 1 [Reference] | NA | 1 [Reference] | NA |
| Black | 25 914 | 187 | 1.27 (1.06-1.53) | .01 | NA | NA |
| Hispanic | 25 359 | 121 | NA | NA | NA | NA |
| Asian | 19 043 | 53 | NA | NA | NA | NA |
| Other | 1688 | 4 | NA | NA | NA | NA |
| Marital status | ||||||
| Unmarried | 97 199 | 526 | 1 [Reference] | NA | 1 [Reference] | NA |
| Married | 127 644 | 389 | 0.73 (0.63-0.84) | <.001 | NA | NA |
| Unknown | 13 883 | 53 | NA | NA | NA | NA |
| Median household income (per $10 000 annual increase) | 238 726 | 968 | NA | NA | NA | NA |
| High school education (per 10% increase) | 238 726 | 968 | NA | NA | NA | NA |
| Insurance status | ||||||
| Uninsured | 4446 | 68 | 1 [Reference] | NA | 1 [Reference] | NA |
| Insured | 229 369 | 876 | 0.60 (0.45-0.79) | <.001 | 0.77 (0.58-1.00) | .05 |
| Unknown | 4911 | 24 | NA | NA | NA | NA |
| Urban | ||||||
| Rural | 25 454 | 117 | 1 [Reference] | NA | 1 [Reference] | NA |
| Urban | 212 934 | 851 | NA | NA | NA | NA |
| Extracranial metastatic sites to bone, lung, and liver, No. | ||||||
| 0 or 1 | 234 640 | 502 | 1 [Reference] | NA | 1 [Reference] | NA |
| 2 | 2755 | 252 | 37.35 (31.78-43.90) | <.001 | 1.65 (1.41-1.94) | <.001 |
| All 3 | 777 | 139 | 75.12 (60.82-92.80) | <.001 | 3.40 (2.76-4.18) | <.001 |
| Unknown | 554 | 75 | 57.17 (43.84-74.56) | <.001 | 3.90 (2.98-5.12) | <.001 |
| Subtype | ||||||
| HR+/HER2− | 162 078 | 361 | 1 [Reference] | NA | 1 [Reference] | NA |
| HR+/HER2+ | 22 376 | 136 | 1.92 (1.57-2.37) | <.001 | 1.41 (1.14-1.73) | .001 |
| HR−/HER2+ | 9719 | 106 | 3.25 (2.57-4.09) | <.001 | 2.09 (1.66-2.64) | <.001 |
| Triple-negative | 25 362 | 173 | 2.61 (2.16-3.15) | <.001 | 2.19 (1.81-2.66) | <.001 |
| Unknown | 19 191 | 192 | 2.68 (2.22-3.24) | <.001 | 1.74 (1.44-2.10) | <.001 |
Abbreviations: HER2, human epidermal growth factor receptor 2; HR, hormone receptor; OR, odds ratio. + Denotes positive; − denotes negative.
a
Only significant results presented (P < .05).
b
Unknown age and unknown race removed from model owing to nonconvergence (n = 920).