Table 2.
Time-dependent univariate and multivariable analysis of associations between clinical and demographic characteristics and thrombosis (n = 47 342)*
| Characteristic | No. (%) | Thrombosis, No. (%) | Univariate HR | Multivariable HR (95% CI) |
| ESA use | ||||
| No | 34 820 | 3400 (9.8) | 1.00 | 1.00 (referent) |
| Yes | 12 522 | 1796 (14.3) | 1.55 | 1.93 (1.79 to 2.07) |
| Age at diagnosis, y | ||||
| 65–69 | 13 443 | 1424 (10.6) | 1.00 | 1.00 (referent) |
| 70–74 | 15 831 | 1843 (11.6) | 1.11 | 1.16 (1.07 to 1.23) |
| 75–79 | 11 235 | 1268 (11.3) | 1.07 | 1.21 (1.11 to 1.30) |
| ≥80 | 6833 | 661 (9.7) | 0.90 | 1.18 (1.07 to 1.28) |
| Race | ||||
| White | 41 535 | 4606 (11.1) | 1.00 | 1.00 (referent) |
| Black | 2801 | 385 (13.8) | 1.28 | 1.20 (1.07 to 1.35) |
| Hispanic | 532 | 48 (9.0) | 0.80 | 0.82 (0.62 to 1.10) |
| Missing or other | 2474 | 157 (6.4%) | 0.54 | 0.68 (0.57 to 0.82) |
| Sex | ||||
| Male | 18 165 | 1784 (9.8) | 1.00 | 1.00 (referent) |
| Female | 29 177 | 3412 (11.7) | 1.22 | 1.10 (1.03 to 1.18) |
| Socioeconomic status | ||||
| Lowest (first) quartile | 14 163 | 1504 (10.6) | 1.00 | 1.00 (referent) |
| Second quartile | 10 745 | 1206 (11.2) | 1.06 | 1.07 (0.99 to 1.16) |
| Third quartile | 10 408 | 1179 (11.3) | 1.07 | 1.03 (0.95 to 1.12) |
| Highest (fourth) quartile | 11 271 | 1207 (10.7) | 1.01 | 0.98 (0.90 to 1.06) |
| Treatment | ||||
| Nonmetastatic | 23 207 | 1970 (8.5) | 1.00 | 1.00 (referent) |
| Metastatic | 15 012 | 1483 (11.6) | 1.42 | 1.53 (1.43 to 1.64) |
| Both | 9123 | 1743 (16.3) | 2.09 | 1.51 (1.41 to 1.62) |
| Radiation therapy | ||||
| No | 24 281 | 2419 (10.0) | 1.00 | 1.00 (referent) |
| Yes | 23 061 | 2777 (12.0) | 1.24 | 1.22 (1.15 to 1.30) |
| Comorbidity score | ||||
| 0 | 26 943 | 2920 (10.8) | 1.00 | 1.00 (referent) |
| 1 | 13 302 | 1416 (10.6) | 0.98 | 1.06 (0.99 to 1.13) |
| >1 | 7097 | 860 (12.1) | 1.13 | 1.32 (1.22 to 1.43) |
| Period | ||||
| 1991–1995 | 12 744 | 1618 (12.7) | 1.00 | 1.00 (referent) |
| 1996–1998 | 12 495 | 1479 (11.8) | 0.92 | 0.98 (0.91 to 1.05) |
| 1999–2002 | 22 103 | 2099 (9.5) | 0.72 | 0.91 (0.84 to 0.99) |
| Tumor | ||||
| Colon | 11 434 | 1259 (11.0) | 1.00 | 1.00 (referent) |
| Breast | 12 499 | 1502 (12.0) | 1.10 | 0.83 (0.75 to 0.92) |
| Lung | 13 786 | 1350 (9.8) | 0.88 | 1.14 (1.00 to 1.29) |
| Diffuse B-cell lymphoma | 9623 | 1085 (11.3) | 1.03 | 1.11 (0.97 to 1.25) |
| Chemotherapy | ||||
| Rituximab | 3557 | 407 (11.4) | 1.15 | 0.85 (0.75 to 0.96) |
| 5-FU | 17 843 | 2074 (11.6) | 1.26 | 1.13 (1.04 to 1.22) |
| Platinum | 10 928 | 1248 (11.4) | 1.10 | 1.18 (1.07 to 1.29) |
| Other | 36 595 | 4195 (11.5) | 1.35 | 1.16 (1.07 to 1.27) |
*
In this analysis, 11% had had either deep vein thrombosis or pulmonary embolism. Each variable was adjusted for the other listed characteristics and for Surveillance, Epidemiology, and End Results site. 5-FU = 5-fluorouracil; CI = confidence interval; ESA = erythropoiesis-stimulating agent; HR = hazard ratio.