Table 3.
Multivariate Logistic Regression Models for Evaluating Predictors of IMRT Diffusion, SEER-Medicare 2002-2006.
| Adjusted predictors for IMRT diffusiona |
|||
|---|---|---|---|
| Characteristics | OR | 95% CI | P |
| Race | |||
| CA | 1.00 | Reference | — |
| AA (urban only) | 0.20 | [0.09, 0.42] | <.0001 |
| Age at diagnosis, (years) | |||
| 66-69 | 1.00 | Reference | — |
| 70-74 | 0.99 | [0.87, 1.13] | .921 |
| ≥75 | 0.93 | [0.82, 1.05] | .0.252 |
| Year of radiation | |||
| 2002 | 1.00 | Reference | — |
| 2003 | 2.93 | [2.53, 3.39] | <.0001 |
| 2004 | 7.69 | [6.62, 8.94] | <.0001 |
| 2005 | 22.40 | [19.03, 26.37] | <.0001 |
| 2006 | 52.00 | [43.31, 62.43] | <.0001 |
| Marital status | |||
| Married | 1.00 | Reference | — |
| Not married/unknown | 1.00 | [0.95, 1.05] | .0987 |
| NCI combined comorbidity score | |||
| 0 | 1.00 | Reference | — |
| >0 | 0.82 | [0.74, 0.90] | <.0001 |
| Income (census tract) | |||
| Quartile 1 (0%-25%) | 1.00 | Reference | — |
| Quartile 2 (26%-50%) | 1.04 | [0.90, 1.21] | .575 |
| Quartile 3 (51%-75%) | 1.18 | [1.00, 1.38] | .0.0496 |
| Quartile 4 (76%-100%) | 1.21 | [0.99, 1.47] | .061 |
| Education (census tract) | |||
| Quartile 1 (0-%25%) | 1.00 | Reference | — |
| Quartile 2 (26%-50%) | 1.30 | [1.12, 1.50] | .0006 |
| Quartile 3 (51%-75%) | 1.69 | [1.43, 2.00] | <.0001 |
| Quartile 4 (76%-100%) | 2.28 | [1.87, 2.77] | <.0001 |
| Population density | |||
| Urban | 1.00 | Reference | — |
| Rural | 0.17 | [0.08, 0.37] | <.0001 |
| Tumor grade | |||
| I | 1.00 | Reference | — |
| II | 0.95 | [0.87, 1.05] | .374 |
| III/IV | 0.81 | [0.63, 1.04] | .099 |
| Clinical stage | |||
| T1/T2 | 1.00 | Reference | — |
| T3/T4 | 0.91 | [0.87-0.96] | .0003 |
| Geographic region | |||
| South | 1.00 | Reference | — |
| Northeast | 2.38 | [2.05, 2.76] | <.0001 |
| Central | 0.90 | [0.77, 1.04] | .159 |
| West | 1.77 | [1.53, 2.04] | <.0001 |
| Interaction terms | |||
| Race (AA) * Urban | 4.39 | 2.17-8.89 | <.0001 |
Note. NCI = National Cancer Institute; SEER = Surveillance, Epidemiology, and End Results; 95% CI = confidence interval; OR = odds radio; AA = African American; CA = Caucasian; IMRT = intensity-modulated radiation therapy. SEER sites were grouped into four geographic regions for analysis.
a
Logistic regression adjusted for race, age (3 categories), year of radiation, marital status, Charlson comorbidity index, income, education, population density, tumor grade, clinical stage, geographic region, and race (AA) * urban.