Table 2.
Multivariable logistic regression for predictors of IMRT
| Characteristic | OR (95% CI) | p-value |
|---|---|---|
| Age (yr) | ||
| ≤67 | Reference | |
| >67 | 0.89 (0.78–1.01) | 0.0636 |
| Chemotherapy | ||
| No | Reference | |
| Yes | 4.98 (4.17–5.96) | <0.0001* |
| Comorbidity score | ||
| 0 | Reference | |
| 1 | 0.99 (0.85–1.14) | 0.8738 |
| ≥2 | 1.28 (1.03–1.60) | 0.0288* |
| Distance from facility (mile) | ||
| ≤11.5 | Reference | |
| >11.5 | 0.92 (0.81–1.04) | 0.1650 |
| Facility type | ||
| Community cancer center | Reference | |
| Comprehensive community cancer center | 1.20 (1.00–1.45) | 0.0564 |
| Academic/research program | 1.35 (1.11–1.63) | 0.0026* |
| Grade | ||
| Well differentiated | Reference | |
| Moderately differentiated | 1.05 (0.90–1.23) | 0.5281 |
| Poorly differentiated | 1.24 (0.99–1.54) | 0.0572 |
| Education (% without a high school diploma) | ||
| ≥29 | Reference | |
| 20–28.9 | 1.03 (0.88–1.20) | 0.7366 |
| 14–19.9 | 0.98 (0.81–1.17) | 0.8012 |
| <14 | 0.92 (0.74–1.14) | 0.4556 |
| Median income by zip code (US dollar) | ||
| <30,000 | Reference | |
| 30,000–34,999 | 0.99 (0.83–1.17) | 0.8681 |
| 35,000–45,999 | 0.98 (0.81–1.18) | 0.7918 |
| ≥46,000 | 1.17 (0.95–1.44) | 0.1376 |
| Insurance | ||
| None | Reference | |
| Private | 0.81 (0.62–1.06) | 0.1278 |
| Government | 0.82 (0.62–1.08) | 0.1614 |
| Location | ||
| Metropolitan | Reference | |
| Urban | 1.21 (1.02–1.42) | 0.0274* |
| Rural | 1.25 (0.87–1.80) | 0.2266 |
| Race | ||
| Caucasian | Reference | |
| African American | 0.89 (0.74–1.06) | 0.1800 |
| Other | 1.08 (0.78–1.48) | 0.6499 |
| Gender | ||
| Male | Reference | |
| Female | 1.12 (0.97–1.30) | 0.1288 |
| Stage | ||
| Tis | Reference | |
| T1 | 0.93 (0.77–1.13) | 0.4665 |
| T2 | 2.12 (1.74–2.59) | <0.0001* |
| Year group | ||
| 2004–2006 | Reference | |
| 2007–2009 | 3.25 (2.63–4.01) | <0.0001* |
| 2010–2012 | 5.10 (4.16–6.25) | <0.0001* |
| 2013–2015 | 5.94 (4.86–7.28) | <0.0001* |
| Dose per fraction (Gy) | ||
| ≤2.0 | Reference | |
| >2.0 | 0.78 (0.70–0.88) | <0.0001* |
IMRT, intensity-modulated radiation therapy; OR, odds ratio; CI, confidence interval.
Bold font indicates statistical significance.
*
p < 0.05, statistical significance.