Table 2.
Univariable and multivariable logistic regression models for undergoing proton therapy
| Univariable (N = 349) |
Multivariable (N = 349) |
|||
|---|---|---|---|---|
| Variable | OR (95%CI) | P-value | OR (95%CI) | P-value |
| Age (years) | 0.96 (0.93-0.98) | .002 | 0.85 (0.71-1.01) | .067 |
| Race | ||||
| Black | 0.30 (0.20-0.47) | <.001 | 0.29 (0.15-0.57) | <.001 |
| Other | 0.52 (0.27-1.00) | .049 | 0.42 (0.20-0.90) | .025 |
| White | Ref | - | - | |
| Povertya | 0.97 (0.96-0.99) | <.001 | 1.03 (0.92-1.14) | .605 |
| Distance (miles) | 1.02 (1.01-1.02) | <.001 | 1.14 (1.06-1.24) | <.001 |
| Primary Insurance | ||||
| Private | 1.16 (0.78-1.72) | .475 | NT | |
| Non-private | Ref | - | - | |
| PSA | 0.91 (0.85-0.96) | <.001 | 0.94 (0.88-1.01) | .076 |
| Gleason Score | ||||
| 3+4=7 | 0.84 (0.54-1.30) | .436 | NT | |
| 4+3=7 | 0.64 (0.37-1.11) | .110 | NT | |
| 3+3=6 | Ref | - | - | |
| T Stage | ||||
| T2 | 1.25 (0.71-2.20) | .433 | NT | |
| T1 | Ref | - | - | |
| Risk Group | ||||
| Low | 1.26 (0.84-1.89) | .274 | NT | |
| Intermediate | Ref | - | - | |
| Prostate Volume (cc) | 0.99 (0.98-1.00) | .011 | 0.99 (0.98-1.00) | .064 |
| IPSS | 1.00 (0.97-1.03) | .968 | NT | |
| IPSS QoL | 0.89 (0.70-1.11) | .302 | NT | |
| IIEF | 1.04 (1.01-1.08) | .007 | 1.01 (0.97-1.05) | .690 |
| Bowel Botherb | 0.99 (0.95-1.03) | .596 | NT | |
| Bowel Functionb | 0.98 (0.94-1.02) | .367 | NT | |
| Androgen Deprivation | ||||
| Yes | 0.56 (0.36-0.88) | .011 | 0.68 (0.39-1.19) | .178 |
| No | Ref | - | - | |
| Physician | ||||
| 1 | 0.34 (0.18-0.64) | .001 | 0.38 (0.18-0.81) | .012 |
| 2 | 0.46 (0.23-0.92) | .027 | 0.60 (0.26-1.36) | .218 |
| 4 | 0.42 (0.22-0.79) | .008 | 0.63 (0.30-1.35) | .2360 |
| Other | 0.56 (0.22-1.42) | .224 | 0.39 (0.14-1.13) | .082 |
| 3 | Ref | - | - | |
| Treatment Year | ||||
| 2011 | 4.54 (2.30-8.99) | <.001 | 4.87 (2.23-10.6) | <.001 |
| 2012 | 6.22 (2.87-13.5) | <.001 | 8.27 (3.43-19.9) | <.001 |
| 2013 | 1.66 (0.91-3.01) | .095 | 1.65 (0.82-3.31) | .161 |
| 2014 | 3.16 (1.53-6.53) | .002 | 4.44 (1.94-10.2) | <.001 |
| 2015 | 0.89 (0.46-1.71) | .720 | 1.09 (0.52-2.29) | .821 |
| 2010 | Ref | - | - | |
CI, confidence interval; IIEF, International Index of Erectile Function; IPSS, International Prostate Symptom Score; NT, not tested; OR, odds ratio; PSA, prostate-specific antigen; QoL, quality of life; Ref, reference value; RBE, relative biological effectiveness.
a
Geocoded census tract for the percentage of those residing below the federal poverty line.
b
Bowel bother and function scores are from the Expanded Prostate Cancer Index Composite.