Summary of injury severity, length of stay and patient outcomes between groups
| No helmet (n=2541) | Helmet (n=2541) | P value | OR (95% CI) | |
| ISS | 6.0 (3.0–14.0) | 5.0 (2.0–13.0) | 0.013 | – |
| GCS <15 | 427 (17.0%) | 252 (10.0%) | <0.001 | 0.54 (0.44 to 0.62) |
| LOS (days) | 1.1 (0.2–3.9) | 0.9 (0.2–3.9) | 0.028 | – |
| ICU LOS (days) | 3.0 (2.0–7.0) | 3.0 (2.0–6.0) | 0.019 | – |
| Total hospital charges (US$), thousands | 37 (18–92) | 33 (16–80) | 0.001 | – |
| Ventilated | 304 (12.0%) | 198 (7.8%) | <0.001 | 0.62 (0.52 to 0.75) |
| ICU admission | 603 (23.7%) | 515 (20.3%) | 0.002 | 0.81 (0.70 to 0.93) |
| Complications (1+) | 222 (8.7%) | 186 (7.3%) | 0.067 | 0.83 (0.67 to 1.01) |
| Died | 136 (5.4%) | 60 (2.4%) | <0.001 | 0.42 (0.31 to 0.58) |
GCS, Glasgow Coma Scale; ICU, intensive care unit; ISS, Injury Severity Score; LOS, length of stay.