Table 2.
Cox proportional hazards regression model of overall survival
| Variable | Univariate analysis
|
Multivariate analysis
|
||
|---|---|---|---|---|
| HR (95% CI) | P-value | HR (95% CI) | P-value | |
| Age (years) | ||||
| ≤50 | Reference | Reference | ||
| >50 | 4.98 (4.50–5.52) | <0.001 | 3.95 (3.20–4.88) | <0.001 |
| Year of diagnosis | ||||
| 1998–2002 | Reference | Reference | ||
| 2003–2007 | 0.87 (0.82–0.93) | <0.001 | 0.82 (0.69–0.97) | 0.019 |
| Race | ||||
| Black | Reference | Reference | ||
| White | 0.68 (0.63–0.75) | <0.001 | 0.76 (0.64–0.90) | 0.001 |
| Other* | 0.43 (0.37–0.49) | <0.001 | 0.59 (0.45–0.79) | <0.001 |
| Marital status | ||||
| Non-married† | Reference | Reference | ||
| Married | 0.52 (0.50–0.55) | <0.001 | 0.55 (0.49–0.62) | <0.001 |
| Poverty–high school index | ||||
| Low SEP | Reference | Reference | ||
| Middle SEP | 0.93 (0.87–0.99) | 0.020 | 1.15 (0.98–1.34) | 0.083 |
| High SEP | 0.75 (0.70–0.81) | <0.001 | 0.92 (0.77–1.10) | 0.359 |
| Laterality | ||||
| Left | Reference | Reference | ||
| Right | 0.99 (0.94–1.05) | 0.822 | 1.02 (0.91–1.15) | 0.745 |
| Primary site | ||||
| Single-quadrant lesions | Reference | Reference | ||
| Multi-quadrant lesions | 1.21 (1.13–1.29) | <0.001 | 1.21 (1.03–1.43) | 0.022 |
| ER status | ||||
| Negative/borderline | Reference | Reference | ||
| Positive | 0.86 (0.76–0.98) | 0.023 | 1.07 (0.88–1.31) | 0.492 |
| PR status | ||||
| Negative/borderline | Reference | Reference | ||
| Positive | 0.82 (0.73–0.92) | <0.001 | 0.84 (0.72–1.00) | 0.043 |
| Grade | ||||
| I | Reference | Reference | ||
| II | 0.89 (0.82–0.97) | 0.009 | 0.99 (0.83–1.18) | 0.922 |
| III and IV | 0.84 (0.77–0.91) | <0.001 | 0.98 (0.82–1.18) | 0.848 |
| RT | ||||
| No | Reference | Reference | ||
| Yes | 0.62 (0.59–0.66) | <0.001 | 0.59 (0.53–0.67) | <0.001 |
Notes:
*
Including American Indian/Alaskan Native and Asian/Pacific Islander.
†
Including divorced, widowed, single (never married), and separated.
Abbreviations: HR, hazard ratio; CI, confidence interval; SEP, socioeconomic position; ER, estrogen receptor; PR, progesterone receptor; RT, radiotherapy.