Table 3.
Multivariable hierarchical logistic regression model for use of the UK-FAST or UK-FAST FORWARD radiation fractionation regimens
| Multivariate model |
|||
|---|---|---|---|
| Patient characteristics | Risk ratio* | 95% CI | P value |
| Age, y | |||
| 18-49 | 1 | ||
| 50-59 | 2.67 | 1.57-3.99 | .001 |
| 60-69 | 4.06 | 2.76-5.25 | <.001 |
| 70 and older | 5.49 | 4.23-6.31 | <.001 |
| Race | |||
| White, non-Hispanic | 1 | ||
| Black, non-Hispanic | 1.12 | 0.74-1.53 | .57 |
| Hispanic | 1.39 | 1.01-1.75 | .05 |
| Other | 1.44 | 0.89-1.94 | .13 |
| Histologic grade | |||
| High | 1 | ||
| Low | 1.63 | 1.14-2.16 | .01 |
| Moderate | 1.49 | 1.08-1.94 | .02 |
| Unknown | 0.61 | 0.04-2.85 | .66 |
| Treatment site | |||
| Whole breast + axilla | 1 | ||
| Whole breast only | 2.65 | 1.62-3.73 | .004 |
| Radiation start | |||
| 2020, Mar-Apr | 1 | ||
| 2020, May-Jun | 12.44 | 3.66-20.09 | <.001 |
| 2020, Jul-Aug | 14.91 | 5.26-20.99 | <.001 |
| 2020, Sept-Oct | 13.22 | 4.12-20.39 | <.001 |
| 2020, Nov-Dec | 13.78 | 4.48-20.6 | <.001 |
| 2021, Jan-Feb | 11.76 | 3.25-19.85 | .001 |
| 2021, Mar-Apr | 11.84 | 3.36-19.82 | .001 |
| 2021, May | 9.97 | 2.28-19.23 | .005 |
| Boost | |||
| Yes | 1 | ||
| No | 1.97 | 1.55-2.38 | <.001 |
| Distance to hospital, miles | |||
| <25 | 1 | ||
| 25-49 | 1.03 | 0.66-1.49 | .89 |
| 50-149 | 1.51 | 1.05-1.99 | .03 |
| ≥150 or international | 1.92 | 1.45-2.35 | <.001 |
Abbreviations: CI = confidence interval; DCIS = ductal carcinoma in situ; HR = hormone receptor; TN = triple-negative.
Bold values indicate statistically significant associations at P<0.05.
⁎
Odds ratios were converted to risk ratios per the method described by Zhang and Yu.11