Demographics of the patient cohort overall and stratified into appropriately restrained and not appropriately restrained (including non-restrained and improperly restrained children)
| Clinical characteristic | Overall n=337 | Not appropriately restrained n=88 | Appropriately restrained n=249 | P value |
| Sex, n (%) | 0.635 | |||
| Female | 165 (49.0) | 45 (51.1) | 120 (48.2) | |
| Male | 172 (51.0) | 43 (48.9) | 129 (51.8) | |
| Age (years), median (IQR) | 4 (1.7–7.0) | 8 (4.0–14.0) | 3 (1.1–5.0) | <0.001 |
| Weight (kg), median (IQR)* | 17 (11.0–27.0) | 33 (18.0–57.0) | 15.0 (9.2–21.5) | <0.001 |
| Race/ethnicity, n (%) | 0.158 | |||
| Asian | 8 (2.4) | 1 (1.1) | 7 (2.8) | |
| Black | 53 (15.7) | 19 (21.6) | 34 (13.7) | |
| Other | 88 (26.1) | 27 (30.7) | 61 (24.5) | |
| White | 30 (8.9) | 5 (5.7) | 25 (10.0) | |
| Hispanic | 158 (46.9) | 36 (40.9) | 122 (49.0) | |
| Primary language, n (%) | 0.616 | |||
| English | 263 (78.0) | 67 (76.1) | 196 (78.7) | |
| Non-English | 74 (22.0) | 21 (23.9) | 53 (21.3) | |
| Insurance type, n (%) | 0.421 | |||
| Public | 250 (74.2) | 69 (78.4) | 181 (72.7) | |
| Private | 53 (15.7) | 10 (11.4) | 43 (17.3) | |
| Other | 34 (10.1) | 9 (10.2) | 25 (10.0) | |
| Injury Severity Score† | 0.007 | |||
| Median (IQR) | 4 (1–10) | 5 (2–14) | 2 (1–10) | |
| Minimum | 1 | 1 | 1 | |
| Maximum | 75 | 75 | 75 | |
| ≥15, n (%) | 42 (17.5) | 16 (18.4) | 26 (10.4) | 0.292 |
| Restraint type, n (%) | <0.001 | |||
| Car seat | 179 (53.1) | 4 (4.6) | 175 (70.3) | |
| Booster seat | 60 (17.8) | 5 (5.7) | 55 (22.1) | |
| Lap belt | 1 (0.3) | 1 (1.1) | 0 (0.0) | |
| Seat belt | 25 (7.4) | 6 (6.8) | 19 (7.6) | |
| None | 72 (21.4) | 72 (81.8) | 0 (0.0) | |
| Childhood Opportunity Index (COI), n (%) | 0.031 | |||
| Very low | 143 (42.4) | 33 (37.5) | 110 (44.2) | |
| Low | 75 (22.3) | 23 (26.1) | 52 (20.9) | |
| Moderate | 61 (18.1) | 10 (11.4) | 51 (20.5) | |
| High | 40 (11.9) | 13 (14.8) | 27 (10.8) | |
| Very high | 18 (5.3) | 9 (10.2) | 9 (3.6) |
*n=323.
†n=240.