Table 4.
Comparison of patient features according to chemotherapy before and after propensity score matching (PSM).
| Characteristics | Unmatched Cohort | 1:1 Propensity Score Matched (PSM) Cohort | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Chemotherapy Not Given | Chemotherapy | Unadjusted | Chemotherapy Not Given | Chemotherapy | PSM-Adjusted | |||||
| N = 325 | % | N = 581 | % | p Value | N = 234 | % | N = 234 | % | p Value | |
| Age at diagnosis | *** | 0.462 | ||||||||
| <50 | 22 | 6.77% | 120 | 20.65% | 21 | 8.97% | 31 | 13.25% | ||
| 50–59 | 68 | 20.92% | 179 | 30.81% | 57 | 24.36% | 64 | 27.35% | ||
| 60–69 | 82 | 25.23% | 170 | 29.26% | 71 | 30.34% | 67 | 28.63% | ||
| 70–79 | 85 | 26.15% | 88 | 15.15% | 56 | 23.93% | 49 | 20.94% | ||
| 80+ | 68 | 20.92% | 24 | 4.13% | 29 | 12.39% | 23 | 9.83% | ||
| Subtype | *** | 0.586 | ||||||||
| HR+/HER2− | 149 | 45.85% | 227 | 39.07% | 114 | 48.72% | 104 | 44.44% | ||
| HR+/HER2+ | 16 | 4.92% | 91 | 15.66% | 16 | 6.84% | 24 | 10.26% | ||
| HR−/HER2+ | 11 | 3.38% | 65 | 11.19% | 11 | 4.70% | 13 | 5.56% | ||
| HR−/HER2− | 33 | 10.15% | 113 | 19.45% | 28 | 11.97% | 33 | 14.10% | ||
| unknown | 116 | 35.69% | 85 | 14.63% | 65 | 27.78% | 60 | 25.64% | ||
| Race | * | 0.778 | ||||||||
| white | 277 | 85.23% | 454 | 78.14% | 199 | 85.04% | 191 | 81.62% | ||
| black | 25 | 7.69% | 70 | 12.05% | 19 | 8.12% | 22 | 9.40% | ||
| other | 20 | 6.15% | 54 | 9.29% | 15 | 6.41% | 20 | 8.55% | ||
| unknown | 3 | 0.92% | 3 | 0.52% | 1 | 0.43% | 1 | 0.43% | ||
| Histological type | *** | 0.668 | ||||||||
| IDC | 64 | 19.69% | 213 | 36.66% | 51 | 21.79% | 57 | 24.36% | ||
| ILC | 37 | 11.38% | 41 | 7.06% | 29 | 12.39% | 24 | 10.26% | ||
| other | 224 | 68.92% | 327 | 56.28% | 154 | 65.81% | 153 | 65.38% | ||
| Marital status | *** | 0.893 | ||||||||
| married | 129 | 39.69% | 323 | 55.59% | 104 | 44.44% | 107 | 45.73% | ||
| divorced/separated/other | 52 | 16.00% | 93 | 16.01% | 40 | 17.09% | 44 | 18.80% | ||
| single | 51 | 15.69% | 83 | 14.29% | 35 | 14.96% | 37 | 15.81% | ||
| widowed | 79 | 24.31% | 66 | 11.36% | 46 | 19.66% | 38 | 16.24% | ||
| unknown | 14 | 4.31% | 16 | 2.75% | 9 | 3.85% | 8 | 3.42% | ||
| N stage | *** | 0.099 | ||||||||
| N0 | 111 | 34.15% | 61 | 10.50% | 59 | 25.21% | 49 | 20.94% | ||
| N1 | 131 | 40.31% | 351 | 60.41% | 115 | 49.15% | 119 | 50.85% | ||
| N2 | 9 | 2.77% | 66 | 11.36% | 9 | 3.85% | 23 | 9.83% | ||
| N3 | 27 | 8.31% | 77 | 13.25% | 25 | 10.68% | 21 | 8.97% | ||
| unknown | 47 | 14.46% | 26 | 4.48% | 26 | 11.11% | 22 | 9.40% | ||
| Grade | *** | 0.076 | ||||||||
| well | 0 | 0.00% | 6 | 1.03% | 0 | 0.00% | 4 | 1.71% | ||
| moderately | 3 | 0.92% | 25 | 4.30% | 3 | 1.28% | 6 | 2.56% | ||
| poorly | 21 | 6.46% | 108 | 18.59% | 20 | 8.55% | 28 | 11.97% | ||
| unknown | 301 | 92.62% | 442 | 76.08% | 211 | 90.17% | 196 | 83.76% | ||
| Median household income (inflation adjusted) | 0.133 | 0.532 | ||||||||
| <45,000$ | 32 | 9.85% | 41 | 7.06% | 24 | 10.26% | 16 | 6.84% | ||
| 45,000–54,999$ | 44 | 13.54% | 77 | 13.25% | 31 | 13.25% | 30 | 12.82% | ||
| 55,000–64,999$ | 86 | 26.46% | 129 | 22.20% | 64 | 27.35% | 59 | 25.21% | ||
| 65,000–74,999$ | 62 | 19.08% | 146 | 25.13% | 42 | 17.95% | 53 | 22.65% | ||
| >74,999$ | 101 | 31.08% | 188 | 32.36% | 73 | 31.20% | 76 | 32.48% | ||
| Surgery | *** | 0.254 | ||||||||
| no | 295 | 90.77% | 381 | 65.58% | 209 | 89.32% | 197 | 84.19% | ||
| yes | 24 | 7.38% | 198 | 34.08% | 24 | 10.26% | 35 | 14.96% | ||
| unknown | 6 | 1.85% | 2 | 0.34% | 1 | 0.43% | 2 | 0.85% | ||
| Radiotherapy | *** | 0.556 | ||||||||
| no/unknown | 245 | 75.38% | 265 | 45.61% | 160 | 68.38% | 153 | 65.38% | ||
| yes | 80 | 24.62% | 316 | 54.39% | 74 | 31.62% | 81 | 34.62% | ||
| Bone metastases | *** | 1 | ||||||||
| no | 160 | 49.23% | 452 | 77.80% | 137 | 58.55% | 137 | 58.55% | ||
| yes | 149 | 45.85% | 121 | 20.83% | 90 | 38.46% | 90 | 38.46% | ||
| unknown | 16 | 4.92% | 8 | 1.38% | 7 | 2.99% | 7 | 2.99% | ||
| Liver metastases | *** | 0.908 | ||||||||
| no | 273 | 84.00% | 525 | 90.36% | 202 | 86.32% | 199 | 85.04% | ||
| yes | 33 | 10.15% | 48 | 8.26% | 25 | 10.68% | 28 | 11.97% | ||
| unknown | 19 | 5.85% | 8 | 1.38% | 7 | 2.99% | 7 | 2.99% | ||
| Lung metastases | *** | 0.876 | ||||||||
| no | 255 | 78.46% | 534 | 91.91% | 196 | 83.76% | 200 | 85.47% | ||
| yes | 52 | 16.00% | 38 | 6.54% | 30 | 12.82% | 27 | 11.54% | ||
| unknown | 18 | 5.54% | 9 | 1.55% | 8 | 3.42% | 7 | 2.99% | ||
| Brain metastases | * | 0.979 | ||||||||
| no | 293 | 90.15% | 545 | 93.80% | 214 | 91.45% | 214 | 91.45% | ||
| yes | 14 | 4.31% | 25 | 4.30% | 12 | 5.13% | 13 | 5.56% | ||
| unknown | 18 | 5.54% | 11 | 1.89% | 8 | 3.42% | 8 | 3.42% | ||
* p < 0.05, *** p < 0.001.