Table 1.
Patient characteristics by group of treatment- unadjusted analysis
| Group | |||
|---|---|---|---|
| ET alone N (%) |
ET plus CDK4/6i N (%) |
P-value | |
| N (%) | 1,747 (44.6%) | 2,170 (55.4%) | |
| Age (mean(SD)) | 68.6 (11.6) | 66.8 (9.7%) | < 0.001 |
| Age | |||
| 18–49 | 151 (8.6%) | 92 (4.2%) | < 0.001 |
| 50–64 | 385 (22.0%) | 762 (35.1%) | |
| 65–74 | 510 (29.2%) | 774 (35.7%) | |
| 75+ | 701 (40.1%) | 542 (25.0%) | |
| Race | |||
| White | 1,125 (64.4%) | 1,423 (65.6%) | 0.8 |
| Black | 157 (9.0%) | 183 (8.4%) | |
| Hispanic | 118 (6.8%) | 154 (7.1%) | |
| All other | 347 (19.9%) | 410 (18.9%) | |
| Practice Type | |||
| Community | 1,571 (89.9%) | 1,935 (89.2%) | 0.4 |
| Academic | 176 (10.1%) | 235 (10.8%) | |
| Stage at initial DX | |||
| I | 220 (12.6%) | 277 (12.8%) | < 0.001 |
| II | 473 (27.1%) | 615 (28.3%) | |
| III | 329 (18.8%) | 295 (13.6%) | |
| IV | 498 (28.5%) | 779 (35.9%) | |
| Not documented | 227 (13.0%) | 204 (9.4%) | |
| Performance Status | |||
| 0 | 587 (40.5%) | 959 (50.2%) | < 0.001 |
| 1 | 517 (35.7%) | 673 (35.2%) | |
| 2+ | 345 (23.8%) | 278 (14.6%) | |
| Metastasis site | |||
| Bone-Only | 569 (32.6%) | 644 (29.7%) | 0.1 |
| Non-Visceral | 405 (23.2%) | 522 (24.1%) | |
| Visceral | 773 (44.2%) | 1,004 (46.3%) | |
| Number of comorbidities | |||
| 0 | 1,079 (61.8%) | 1,320 (60.8%) | < 0.001 |
| 1 | 464 (26.6%) | 638 (29.4%) | |
| 2+ | 204 (11.7%) | 212 (9.8%) | |
| Health insurance type | |||
| Commercial/Medicaid | 36 (2.1%) | 49 (2.3%) | < 0.001 |
| Commercial | 209 (12.3%) | 384 (18.1%) | |
| Commercial/Other | 116 (6.9%) | 212 (10.0%) | |
| Medicaid only | 25 (1.5%) | 26 (1.2%) | |
| Medicare | 313 (18.5%) | 280 (13.2%) | |
| Medicare/Medicaid | 64 (3.8%) | 68 (3.2%) | |
| Medicare/other | 791 (46.7%) | 941 (44.3%) | |
| None | 139 (8.2%) | 166 (7.8%) | |
| ET backbone | |||
| Anastrozole | 561 (32.1%) | 211 (9.7%) | < 0.001 |
| Anastrozole, Fulvestrant | 34 (1.9%) | 6 (0.3%) | |
| Exemestane | 124 (7.1%) | 46 (2.1%) | |
| Exemestane, Fulvestrant | 6 (0.3%) | 6 (0.3%) | |
| Fulvestrant | 278 (15.9%) | 604 (27.8%) | |
| Letrozole | 499 (28.5%) | 1,277 (58.8%) | |
| Letrozole, Fulvestrant | 9 (0.5%) | 12 (0.6%) | |
| Tamoxifen | 232 (13.3%) | 7 (0.3%) | |
| Tamoxifen, Fulvestrant | 4 (0.2%) | 1 (0.0%) | |
| Backbone CDK4/6i | |||
| Abemaciclib | - | 178 (8.2%) | - |
| Abemaciclib, Ribociclib | - | 2 (0.1%) | |
| Palbociclib | - | 1,793 (82.6%) | |
| Palbociclib, Abemaciclib | - | 24 (1.1%) | |
| Palbociclib, Ribociclib | - | 7 (0.3%) | |
| Ribociclib | - | 166 (7.6%) | |