Table 2.
Patient clinical characteristics.
| Unadjusted cohort | Cohort after stabilized inverse probability treatment weighting | Cohort after propensity score matching | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Characteristic | Palbociclib + aromatase inhibitor (n = 1324) | Aromatase inhibitor alone (n = 1564) | Standardized difference | Palbociclib + Aromatase Inhibitor (n = 1572) | Aromatase inhibitor alone (n = 1137) | Standardized difference | Palbociclib + aromatase inhibitor (n = 939) | Aromatase inhibitor alone (n = 939) | Standardized difference |
| Disease stage at initial diagnosis, n (%) | |||||||||
| I | 147 (11.1) | 216 (13.8) | −0.0821 | 198 (12.6) | 145 (12.8) | −0.0060 | 114 (12.1) | 121 (12.9) | −0.0225 |
| II | 345 (26.1) | 418 (26.7) | −0.0152 | 407 (25.9) | 300 (26.4) | −0.0118 | 262 (27.9) | 247 (26.3) | 0.0359 |
| III | 181 (13.7) | 297 (19.0) | −0.1443 | 261 (16.6) | 188 (16.6) | 0.0011 | 144 (15.3) | 150 (16.0) | −0.0176 |
| IV | 541 (40.9) | 464 (29.7) | 0.2359 | 530 (33.7) | 390 (34.3) | −0.0110 | 323 (34.4) | 323 (34.4) | 0.0000 |
| Not documented | 110 (8.3) | 169 (10.8) | −0.0850 | 176 (11.2) | 114 (10.0) | 0.0389 | 96 (10.2) | 98 (10.4) | −0.0070 |
| Eastern Cooperative Oncology Group performance status, n (%) | |||||||||
| 0 | 499 (37.7) | 397 (25.4) | 0.2672 | 472 (30.1) | 348 (30.6) | −0.0126 | 273 (29.1) | 304 (32.4) | −0.0716 |
| 1 | 318 (24.0) | 334 (21.4) | 0.0636 | 362 (23.0) | 259 (22.8) | 0.0066 | 228 (24.3) | 225 (24.0) | 0.0075 |
| 2, 3, or 4 | 153 (11.6) | 271 (17.3) | −0.1647 | 251 (15.9) | 169 (14.9) | 0.0290 | 137 (14.6) | 118 (12.6) | 0.0591 |
| Not documented | 354 (26.7) | 562 (35.9) | −0.1992 | 487 (31.0) | 361 (31.7) | −0.0160 | 301 (32.1) | 292 (31.1) | 0.0206 |
| Visceral disease, n (%) | 444 (33.5) | 404 (25.8) | −0.1692 | 460 (29.3) | 337 (29.7) | 0.0085 | 295 (31.4) | 293 (31.2) | −0.0046 |
| Bone-only disease, n (%) | 519 (39.2) | 599 (38.3) | −0.0185 | 589 (37.5) | 440 (38.7) | 0.0253 | 373 (39.7) | 403 (42.9) | 0.0649 |
| Brain metastases, n (%) | 26 (2.0) | 50 (3.2) | 0.0778 | 26 (1.7) | 43 (3.8) | 0.1310 | 18 (1.9) | 39 (4.2) | 0.1306 |
| Interval from initial breast cancer diagnosis to metastatic breast cancer diagnosis, n (%), y | |||||||||
| De novo | 541 (40.9) | 464 (29.7) | 0.2359 | 530 (33.7) | 390 (34.3) | −0.0110 | 323 (34.4) | 323 (34.4) | 0.0000 |
| ≤1 | 40 (3.0) | 66 (4.2) | −0.0642 | 74 (4.7) | 43 (3.8) | 0.0442 | 34 (3.6) | 41 (4.4) | −0.0381 |
| >1–5 | 191 (14.4) | 429 (27.4) | −0.3238 | 271 (17.2) | 288 (25.4) | −0.1992 | 151 (16.1) | 230 (24.5) | −0.2104 |
| >5 | 551 (41.6) | 601 (38.4) | 0.0651 | 696 (44.3) | 414 (36.4) | 0.1612 | 430 (45.8) | 343 (36.5) | 0.1891 |
| Not documented | 1 (0.08) | 4 (0.3) | −0.0443 | 1 (0.05) | 2 (0.2) | −0.0388 | 1 (0.11) | 2 (0.21) | −0.0267 |
| National Cancer Institute comorbidity index, mean (SD) | 0.29 (0.47) | 0.39 (0.52) | −0.2096 | 0.33 (0.57) | 0.36 (0.42) | −0.0632 | 0.31 (0.5) | 0.34 (0.5) | −0.0709 |
| Number of metastatic sites, n (%) | |||||||||
| 1 | 654 (49.4) | 843 (53.9) | −0.0902 | 793 (50.4) | 589 (51.8) | −0.0273 | 498 (53.0) | 526 (56.0) | −0.0599 |
| 2 | 367 (27.7) | 291 (18.6) | 0.2173 | 352 (22.4) | 261 (22.9) | −0.0136 | 244 (26.0) | 222 (23.6) | 0.0543 |
| 3 | 178 (13.4) | 133 (8.5) | 0.1586 | 158 (10.1) | 129 (11.3) | −0.0413 | 106 (11.3) | 107 (11.4) | −0.0034 |
| 4 | 56 (4.2) | 31 (2.0) | 0.1298 | 51 (3.3) | 27 (2.4) | 0.0501 | 36 (3.8) | 30 (3.2) | 0.0347 |
| ≥5 | 33 (2.5) | 22 (1.4) | 0.0786 | 33 (2.1) | 20 (1.7) | 0.0256 | 19 (2.0) | 18 (1.9) | 0.0077 |
| Not documented | 36 (2.7) | 244 (15.6) | −0.4581 | 186 (11.8) | 111 (9.8) | 0.0654 | 36 (3.8) | 36 (3.8) | 0.0000 |
| Median follow-up duration (IQR), mo | 25.0 (13.8–38.3) | 23.3 (11.8–42.3) | −0.0049 | 23.9 (12.8–38.0) | 24.5 (12.0–42.9) | −0.0829 | 23.4 (13.1–37.8) | 24.94 (12.4–44.4) | −0.1082 |