Table 3.
Logistic Regression Models of Radiation Therapy Receipt
| Variable | Model 1 |
Model 2 |
||||||
|---|---|---|---|---|---|---|---|---|
| Odds Ratio | 95% CI | P* | Odds Ratio | 95% CI | P* | |||
| Surgery type | < .001 | < .001 | ||||||
| Mastectomy | 1.00 | — | — | 1.00 | — | — | ||
| BCS | 5.92 | 4.62 | 7.58 | 4.46 | 3.34 | 5.96 | ||
| Indication strength and site† | .003 | |||||||
| Weaker indication, LA | 1.00 | — | — | 1.00 | — | — | ||
| Weaker indication, Detroit | 2.63 | 1.82 | 3.80 | 2.54 | 1.68 | 3.83 | ||
| Strong indication, LA | 6.35 | 4.72 | 8.54 | 7.94 | 5.60 | 11.26 | ||
| Strong indication, Detroit | 7.97 | 4.88 | 13.03 | 8.85 | 5.10 | 15.34 | ||
| Comorbidities | < .001 | < .001 | ||||||
| 0 | 1.00 | — | — | 1.00 | — | — | ||
| 1 | 0.79 | 0.59 | 1.06 | 0.78 | 0.57 | 1.09 | ||
| ≥ 2 | 0.47 | 0.34 | 0.64 | 0.48 | 0.34 | 0.68 | ||
| Age, years | .011 | .005 | ||||||
| < 40 | 1.19 | 0.62 | 2.29 | 0.91 | 0.45 | 1.86 | ||
| 40-49 | 1.27 | 0.76 | 2.11 | 1.22 | 0.69 | 2.17 | ||
| 50-59 | 1.72 | 1.06 | 2.79 | 1.45 | 0.84 | 2.50 | ||
| 60-69 | 0.93 | 0.62 | 1.39 | 0.73 | 0.47 | 1.15 | ||
| ≥ 70 | 1.00 | — | — | 1.00 | — | — | ||
| Ethnicity | .815 | .553 | ||||||
| White | 1.00 | — | — | 1.00 | — | — | ||
| Black | 1.15 | 0.84 | 1.59 | 1.20 | 0.85 | 1.71 | ||
| Latina | 1.11 | 0.78 | 1.58 | 1.23 | 0.84 | 1.81 | ||
| Other | 1.20 | 0.26 | 5.60 | 1.65 | 0.33 | 8.31 | ||
| Income, $ | .027 | .033 | ||||||
| < 20,000 | 1.00 | — | — | 1.00 | — | — | ||
| 20,000-69,999 | 1.22 | 0.87 | 1.71 | 1.04 | 0.71 | 1.52 | ||
| ≥ 70,000 | 1.14 | 0.77 | 1.70 | 1.24 | 0.78 | 1.95 | ||
| Unknown | 1.73 | 1.18 | 2.54 | 1.71 | 1.10 | 2.64 | ||
| Education | .092 | .121 | ||||||
| Not HS graduate | 1.00 | — | — | 1.00 | — | — | ||
| HS graduate | 1.20 | 0.81 | 1.77 | 1.29 | 0.83 | 1.99 | ||
| Some college | 1.22 | 0.84 | 1.77 | 0.88 | 0.59 | 1.33 | ||
| College graduate | 1.63 | 1.08 | 2.47 | 1.16 | 0.73 | 1.82 | ||
| Insurance | .058 | .677 | ||||||
| None | 0.55 | 0.34 | 0.92 | 0.74 | 0.42 | 1.31 | ||
| Medicaid | 1.05 | 0.66 | 1.69 | 1.09 | 0.65 | 1.82 | ||
| Medicare | 1.19 | 0.80 | 1.75 | 1.04 | 0.67 | 1.61 | ||
| Other | 1.00 | — | — | 1.00 | — | — | ||
| Surgeon participation | — | — | — | — | < .001 | |||
| Lower | — | — | — | — | 1.00 | — | — | |
| High | — | — | — | — | 2.33 | 1.80 | 3.02 | |
| Desire to avoid radiation | < .001 | |||||||
| Lower | — | — | — | — | 1.00 | — | — | |
| High | — | — | — | — | 0.35 | 0.27 | 0.44 | |
Abbreviations: BCS, breast-conserving surgery; LA, Los Angeles; HS, high school.
*
P values for group variables are reported from Wald tests.
†
Model 1: P value for indication strength < .001; P value for site < .001; P value for interaction = .003. Model 2: P value for indication strength < .001; P value for site < .001; P value for interaction = .003.