Table 2.
Individual descriptive statistics by poverty quartile
| First quartile (<6.5%) n=103 004 |
Second quartile (6.5%–10.8%) n=79 738 |
Third quartile (10.8%–18.7%) n=90 554 |
Fourth quartile (>18.7%) n=134 257 |
P values* | |
| Age, mean (95% CI) | 63.9 (63.7 to 64.0) | 65.1 (64.9 to 65.2) | 62.3 (62.1 to 62.4) | 53.8 (53.6 to 53.9) | <0.001 |
| Female (%) | 53.0 | 54.0 | 52.0 | 43.4 | <0.001 |
| Race (%) | <0.001 | ||||
| White | 86.9 | 93.5 | 83.1 | 38.5 | |
| Black | 9.5 | 3.3 | 13.7 | 56.3 | |
| Other | 3.6 | 3.2 | 3.2 | 5.2 | |
| Mechanism (%) | <0.001 | ||||
| Falls | 49.8 | 51.7 | 47.3 | 35.4 | |
| Firearms | 1.0 | 0.4 | 1.0 | 5.1 | |
| Motor vehicle | 8.0 | 7.6 | 8.1 | 9.6 | |
| Severity (ISS), mean (95% CI) | 5.0 (4.9 to 5.0) | 4.9 (4.9 to 4.9) | 4.7 (4.7 to 4.7) | 4.9 (4.9 to 5.0) | <0.001 |
| Comorbidities, mean (95% CI) | 2.7 (2.7 to 2.7) | 2.8 (2.8 to 2.8) | 2.9 (2.8 to 2.9) | 2.7 (2.7 to 2.7) | <0.001 |
| Mortality (%) | 2.4 | 2.5 | 2.4 | 2.6 | 0.002 |
| LOS, median (IQR) | 4.0 (2.0–7.0) | 4.0 (2.0–7.0) | 4.0 (2.0–7.0) | 4.0 (2.0–8.0) | <0.001 |
| Charges (thousands of dollars), median (IQR) | 22.2 (13.0–37.8) | 22.7 (13.2–38.9) | 22.3 (13.0–38.0) | 23.3 (13.3–41.7) | <0.001 |
*P values for one-way analysis of variance (age, ISS), Kruskal-Wallis (LOS, cost) or χ2 (female, race, mechanism, mortality).
ISS, Injury Severity Score; LOS, length of stay.