TABLE 4.
Adjusted Population Measure Incidence Rate Ratios (IRRs) for Major Trauma Events Across the 6 US Sites: Resuscitation Outcomes Consortium Epistry-Trauma Project, United States, 2005–2007
| Major Trauma (n = 4666), IRR (95% CI) | Death in Field (n = 645), IRR (95% CI) | Penetrating Injury (n = 1082), IRR (95% CI) | Intentional Injury (n = 1416), IRR (95% CI) | |
| Men, % | … | 1.0003 (1.00001, 1.0005) | … | … |
| Unemployment, % | 1.03 (1.02, 1.04) | … | 1.02 (1.01, 1.03) | 1.02 (1.01, 1.03) |
| Non–primary language use, %a | ||||
| Quartile 1 (Ref) | 1.00 | 1.00 | 1.00 | 1.00 |
| Quartile 2 | 0.81 (0.72, 0.93) | 0.66 (0.52, 0.86) | 0.80 (0.65, 0.99) | 0.84 (0.69, 1.02) |
| Quartile 3 | 0.70 (0.59, 0.83) | 0.47 (0.34, 0.66) | 0.57 (0.44, 0.75) | 0.61 (0.48, 0.78) |
| Quartile 4 | 0.62 (0.48, 0.81) | 0.30 (0.18, 0.49) | 0.37 (0.26, 0.55) | 0.42 (0.29, 0.59) |
| Median household size | 0.51 (0.44, 0.59) | 0.56 (0.43, 0.74) | 0.65 (0.53, 0.81) | 0.60 (0.49, 0.73) |
| Median age, y | 1.01 (1.00, 1.02) | … | … | … |
| Median household income, $a | ||||
| Quartile 1 (Ref) | 1.00 | 1.00 | 1.00 | 1.00 |
| Quartile 2 | 0.77 (0.66, 0.90) | 0.74 (0.56, 0.98) | 0.63 (0.50, 0.79) | 0.65 (0.52, 0.80) |
| Quartile 3 | 0.73 (0.59, 0.90) | 0.60 (0.40, 0.88) | 0.45 (0.33, 0.62) | 0.46 (0.34, 0.61) |
| Quartile 4 | 0.72 (0.56, 0.93) | 0.42 (0.25, 0.70) | 0.37 (0.24, 0.55) | 0.41 (0.28, 0.60) |
| High school diploma, % | 0.97 (0.97, 0.98) | 0.98 (0.96, 0.99) | 0.98 (0.97, 0.99) | 0.97 (0.96, 0.98) |
| Non-White, %a | ||||
| Quartile 1 (Ref) | 1.00 | 1.00 | 1.00 | 1.00 |
| Quartile 2 | 0.99 (0.83, 1.18) | 0.74 (0.51, 1.06) | 1.09 (0.76, 1.56) | 0.96 (0.70, 1.32) |
| Quartile 3 | 1.24 (1.03, 1.49) | 0.93 (0.64, 1.34) | 1.57 (1.10, 2.24) | 1.47 (1.08, 2.02) |
| Quartile 4 | 1.50 (1.22, 1.85) | 1.50 (1.03, 2.17) | 2.87 (1.99, 4.14) | 2.48 (1.78, 3.44) |
| Hispanic, %a | ||||
| Quartile 1 (Ref) | 1.00 | 1.00 | 1.00 | 1.00 |
| Quartile 2 | … | … | … | … |
| Quartile 3 | … | … | … | … |
| Quartile 4 | … | … | … | … |
| Site | ||||
| 1 (Ref) | 1.00 | 1.00 | 1.00 | 1.00 |
| 2 | 1.28 (1.04, 1.57) | 1.48 (1.01, 2.16) | 1.33 (0.97, 1.81) | 1.37 (1.03, 1.84) |
| 3 | 1.63 (1.35, 1.98) | 1.49 (1.07, 2.09) | 1.59 (1.20, 2.12) | 1.64 (1.25, 2.15) |
| 4 | 1.60 (1.26, 2.04) | 1.39 (0.90, 2.15) | 1.81 (1.28, 2.54) | 1.79 (1.29, 2.48) |
| 5 | 1.00 (0.80, 1.25) | 0.58 (0.36, 0.94) | 0.59 (0.38, 0.89) | 0.74 (0.51, 1.07) |
| 6 | 3.31 (2.70, 4.06) | 2.17 (1.48, 3.20) | 3.29 (2.38, 4.54) | 4.12 (3.05, 5.58) |
Note. CI = confidence interval. Data were based on 1923 census tracts. Estimates were obtained via multivariable negative binomial models with patient count as the outcome. The census tract was the unit of analysis. The analysis was limited to US sites because race and ethnicity data were not consistently included in Canadian census data. The 6 US study sites were Birmingham, Alabama; Dallas, Texas; Milwaukee, Wisconsin; Pittsburgh, Pennsylvania; Portland, Oregon; King County, Washington; Ellipses indicate covariates dropped from the final model.
Quartile 1 = 0–25th percentile; quartile 2 = 26th–50th percentile; quartile 3 = 51st–75th percentile; quartile 4 = 76th–100th percentile.