Table A2.
Results of Two-Stage Linear Probability Model, Using Differential Distance As Instrumental Variable
| Variable | Any Complication |
Wound and Skin Complications |
Deep-Tissue and Bone Complications |
||||||
|---|---|---|---|---|---|---|---|---|---|
| Coefficient | 95% CI | P | Coefficient | 95% CI | P | Coefficient | 95% CI | P | |
| Intercept | 0.184 | 0.141 to 0.227 | < .001 | 0.168 | 0.126 to 0.209 | < .001 | 0.025 | 0.004 to 0.046 | .017 |
| Radiation modality | |||||||||
| Whole-breast irradiation | Ref | Ref | Ref | ||||||
| Brachytherapy | 0.168 | 0.096 to 0.240 | < .001 | 0.169 | 0.100 to 0.238 | < .001 | 0.019 | −0.015 to 0.054 | .28 |
| Age at breast-conserving surgery, years | |||||||||
| 66-69 | Ref | Ref | Ref | ||||||
| 70-74 | 0.008 | −0.009 to 0.025 | .36 | 0.012 | −0.005 to 0.028 | .16 | −0.005 | −0.013 to 0.003 | .23 |
| 75-79 | 0.010 | −0.008 to 0.028 | .28 | 0.007 | −0.011 to 0.025 | .44 | 0.001 | −0.008 to 0.009 | .88 |
| 80-84 | 0.014 | −0.007 to 0.035 | .19 | 0.014 | −0.006 to 0.034 | .17 | 0.004 | −0.006 to 0.014 | .41 |
| 85-94 | 0.011 | −0.019 to 0.041 | .48 | 0.001 | −0.028 to 0.030 | .93 | 0.012 | −0.003 to 0.026 | .12 |
| Race | |||||||||
| White | Ref | Ref | Ref | ||||||
| Black | −0.026 | −0.054 to 0.001 | .06 | −0.017 | −0.043 to 0.010 | .22 | −0.011 | −0.024 to 0.002 | .09 |
| Other | −0.030 | −0.069 to 0.009 | .13 | −0.028 | −0.066 to 0.009 | .14 | −0.003 | −0.021 to 0.016 | .78 |
| Income | |||||||||
| Q1 (≤ $33,208) | Ref | Ref | Ref | ||||||
| Q2 ($33,209-$39,659) | 0.002 | −0.019 to 0.023 | .84 | 0.005 | −0.015 to 0.025 | .64 | −0.002 | −0.012 to 0.008 | .70 |
| Q3 ($39,661-$47,295) | 0.012 | −0.009 to 0.032 | .27 | 0.011 | −0.009 to 0.031 | .29 | 0.002 | −0.008 to 0.011 | .77 |
| Q4 ($47,300-$60,118) | 0.010 | −0.011 to 0.031 | .35 | 0.007 | −0.013 to 0.027 | .47 | 0.003 | −0.007 to 0.013 | .53 |
| Q5 (≥ $60,124) | 0.011 | −0.010 to 0.032 | .29 | 0.013 | −0.008 to 0.033 | .22 | 0.001 | −0.009 to 0.011 | .89 |
| Unknown | 0.013 | −0.024 to 0.051 | .49 | 0.003 | −0.033 to 0.039 | .87 | 0.005 | −0.013 to 0.023 | .55 |
| Comorbidity | |||||||||
| 0 conditions | Ref | Ref | Ref | ||||||
| 1-2 conditions | 0.052 | 0.038 to 0.066 | < .001 | 0.041 | 0.028 to 0.055 | < .001 | 0.017 | 0.011 to 0.024 | < .001 |
| ≥ 3 conditions | 0.114 | 0.087 to 0.142 | < .001 | 0.085 | 0.059 to 0.111 | < .001 | 0.055 | 0.042 to 0.068 | < .001 |
| Type of radiation facility | |||||||||
| Hospital-based | Ref | Ref | Ref | ||||||
| Free-standing | −0.009 | −0.022 to 0.004 | .18 | −0.008 | −0.021 to 0.005 | .21 | 0.000 | −0.007 to 0.006 | .95 |
| Axillary node dissection | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | −0.006 | −0.020 to 0.009 | .46 | −0.002 | −0.016 to 0.012 | .76 | −0.001 | −0.008 to 0.006 | .88 |
| Chemotherapy | |||||||||
| No chemotherapy | Ref | Ref | Ref | ||||||
| Chemotherapy started in month prior through month after surgery | 0.032 | −0.003 to 0.067 | .07 | 0.025 | −0.009 to 0.058 | .15 | 0.010 | −0.007 to 0.026 | .24 |
| Chemotherapy started 31-365 days after surgery | 0.061 | 0.038 to 0.085 | < .001 | 0.057 | 0.035 to 0.080 | < .001 | 0.019 | 0.007 to 0.030 | .001 |
| Hospital admission* | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | 0.022 | 0.001 to 0.042 | .04 | 0.014 | −0.006 to 0.034 | .16 | 0.017 | 0.007 to 0.027 | .001 |
| Screening mammogram* | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | −0.017 | −0.033 to −0.002 | .03 | −0.015 | −0.030 to 0.000 | .05 | −0.006 | −0.013 to 0.002 | .14 |
| Visit to primary care physician* | |||||||||
| No | Ref | Ref | Ref | ||||||
| Yes | 0.047 | 0.009 to 0.085 | .02 | 0.033 | −0.003 to 0.070 | .07 | 0.011 | −0.007 to 0.030 | .22 |
Abbreviation: Ref, reference.
*
In the year before breast-conserving surgery.