Original cohort | Propensity score-matched cohort | |||||||
---|---|---|---|---|---|---|---|---|
Parameters | Helmet use Yes n = 7735 | Helmet use No n = 863 | Odds ratio (95%) | P | Helmet use Yes n = 856 | Helmet use No n = 856 | Odds ratio (95%) | P |
Physiology at ED, n (%) | ||||||||
SBP < 90 mmHg | 163(2.1) | 24(2.8) | 0.8(0.49–1.16) | 0.198 | 18(2.1) | 24(2.8) | 0.7(0.40–1.38) | 0.349 |
Heart rate > 100 beats/min | 1363(17.6) | 182(21.1) | 0.8(0.67–0.95) | 0.012 | 159(18.6) | 181(21.1) | 0.9(0.67–1.08) | 0.183 |
Respiratory rate < 10 or >29 /min | 34(0.4) | 11(1.3) | 0.3(0.17–0.68) | 0.004 | 5(0.6) | 11(1.3) | 0.5(0.16–1.31) | 0.132 |
Procedures at ED, n (%) | ||||||||
Cardiopulmonary resuscitation | 8(0.1) | 2(0.2) | 0.4(0.09–2.10) | 0.265 | 1(0.1) | 2(0.2) | 0.5(0.05–5.52) | 1.000 |
Intubation | 147(1.9) | 57(6.6) | 0.3(0.20–0.38) | <0.001 | 17(2.0) | 57(6.7) | 0.3(0.16–0.49) | <0.001 |
Chest tube insertion | 108(1.4) | 16(1.9) | 0.8(0.44–1.27) | 0.285 | 14(1.6) | 16(1.9) | 0.9(0.42–1.80) | 0.713 |
Blood transfusion | 266(3.4) | 38(4.4) | 0.8(0.55–1.09) | 0.146 | 37(4.3) | 38(4.4) | 1.0(0.61–1.55) | 0.906 |