Background
Methods
Results
Demographics and injury characteristics of patients
Covariates and outcome of the patients
Before matching | After matching | |||||||
---|---|---|---|---|---|---|---|---|
Covariates | Helmet use Yes n = 7735 | Helmet use No n = 863 |
Odds ratio
(95%CI)
|
P
| Helmet use Yes n = 856 | Helmet use No n = 856 | Mean Difference | Standardized Difference |
Age | 46.0 ± 17.5 | 48.8 ± 18.6 | — | <0.001 | 48.6 ± 18.6 | 48.6 ± 18.6 | −0.01168 | −0.06(%) |
Sex | ||||||||
Male | 4248(54.9) | 592(68.6) | 0.6(0.48–0.65) | <0.001 | 588(68.7) | 588(68.7) | 1.0(0.82–1.23) | 0.00(%) |
Female | 3487(45.1) | 271(31.4) | 1.8(1.54–2.09) | <0.001 | 268(31.3) | 268(31.3) | 1.0(0.82–1.23) | 0.00 (%) |
Comorbidity | ||||||||
DM | 831(10.7) | 106(12.3) | 0.9(0.69–1.07) | 0.169 | 102(11.9) | 102(11.9) | 1.0(0.75–1.34) | 0.00 (%) |
HTN | 1539(19.9) | 201(23.3) | 0.8(0.69–0.97) | 0.019 | 197(23.0) | 197(23.0) | 1.0(0.80–1.25) | 0.00 (%) |
CAD | 156(2.0) | 23(2.7) | 0.8(0.48–1.17) | 0.206 | 20(2.3) | 20(2.3) | 1.0(0.53–1.87) | 0.00 (%) |
CHF | 27(0.3) | 7(0.8) | 0.4(0.19–0.99) | 0.076 | 4(0.5) | 4(0.5) | 1.0(0.25–4.01) | 0.00 (%) |
CVA | 95(1.2) | 15(1.7) | 0.7(0.41–1.22) | 0.206 | 11(1.3) | 11(1.3) | 1.0(0.43–2.32) | 0.00 (%) |
ESRD | 2(0.0) | 0(0.0) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
Outcome | ||||||||
GCS | 14.4 ± 2.1 | 12.8 ± 3.8 | — | <0.001 | 14.4 ± 2.0 | 12.8 ± 3.8 | — | <0.001 |
≤ 8 | 305(3.9) | 145(16.8) | 0.2(0.16–0.25) | <0.001 | 34(4.0) | 145(16.9) | 0.2(0.14–0.30) | <0.001 |
9–12 | 256(3.3) | 79(9.2) | 0.3(0.26–0.44) | <0.001 | 31(3.6) | 77(9.0) | 0.4(0.25–0.58) | <0.001 |
≥ 13 | 7174(92.7) | 639(74.0) | 4.5(3.76–5.34) | <0.001 | 791(92.4) | 634(74.1) | 4.3(3.17–5.73) | <0.001 |
AIS ≥ 3, n (%) | ||||||||
Head/Neck | 1288(16.7) | 399(46.2) | 0.2(0.20–0.27) | <0.001 | 149(17.4) | 398(46.5) | 0.2(0.19–0.30) | <0.001 |
Face | 22(0.3) | 7(0.8) | 0.3(0.15–0.82) | 0.022 | 4(0.5) | 7(0.8) | 0.6(0.17–1.95) | 0.364 |
Thorax | 685(8.9) | 105(12.2) | 0.7(0.56–0.87) | 0.001 | 98(11.4) | 104(12.1) | 0.9(0.70–1.25) | 0.653 |
Abdomen | 192(2.5) | 21(2.4) | 1.0(0.65–1.61) | 0.930 | 21(2.5) | 21(2.5) | 1.0(0.54–1.85) | 1.000 |
Extremity | 1898(24.5) | 138(16.0) | 1.7(1.41–2.06) | <0.001 | 190(22.2) | 137(16.0) | 1.5(1.17–1.91) | 0.001 |
ISS, median (IQR) | 8(4–10) | 10(5–18) | — | <0.001 | 9(4–12) | 10(5–18) | — | <0.001 |
< 16 | 6570(84.9) | 530(61.4) | 3.5(3.05–4.12) | <0.001 | 687(80.3) | 524(61.2) | 2.6(2.07–3.20) | <0.001 |
16–24 | 829(10.7) | 224(26.0) | 0.3(0.29–0.41) | <0.001 | 144(16.8) | 223(26.1) | 0.6(0.45–0.73) | <0.001 |
≥ 25 | 336(4.3) | 109(12.6) | 0.3(0.25–0.40) | <0.001 | 25(2.9) | 109(12.7) | 0.2(0.13–0.32) | <0.001 |
Hospital LOS (days) | 9.5 ± 9.7 | 12.0 ± 12.9 | — | <0.001 | 9.5 ± 9.7 | 12.0 ± 12.9 | — | <0.001 |
ICU | ||||||||
Patients, n (%) | 1291(16.7) | 338(39.2) | 0.3(0.27–0.36) | <0.001 | 156(18.2) | 336(39.3) | 0.3(0.28–0.43) | <0.001 |
< 16 | 447(5.8) | 85(9.8) | 0.6(0.44–0.72) | <0.001 | 48(5.6) | 84(9.8) | 0.5(0.38–0.80) | 0.001 |
16–24 | 545(7.0) | 155(18.0) | 0.3(0.29–0.42) | <0.001 | 83(9.7) | 154(18.0) | 0.5(0.37–0.65) | <0.001 |
≥ 25 | 299(3.9) | 98(11.4) | 0.3(0.25–0.40) | <0.001 | 25(2.9) | 98(11.4) | 0.2(0.15–0.37) | <0.001 |
ICU LOS (days) | 6.9 ± 8.3 | 7.6 ± 9.0 | — | 0.172 | 6.1 ± 6.8 | 7.6 ± 9.1 | — | 0.043 |
Mortality | 83(1.1) | 36(4.2) | 0.2(0.17–0.37) | <0.001 | 7(0.8) | 36(4.2) | 0.2(0.09–0.44) | <0.001 |
Before matching | After matching | |||||||
---|---|---|---|---|---|---|---|---|
Covariates | Helmet use Yes n = 76 | Helmet use No n = 647 |
Odds ratio
(95%CI)
|
P
| Helmet use Yes n = 76 | Helmet use No n = 76 | Mean Difference | Standardized Difference |
Age | 48.8 ± 13.7 | 63.1 ± 15.6 | — | <0.001 | 48.8 ± 13.7 | 48.7 ± 13.8 | 0.09211 | 0.67(%) |
Sex | ||||||||
Male | 60(78.9) | 355(54.9) | 3.1(1.74–5.47) | <0.001 | 60(78.9) | 60(78.9) | 1.0(0.46–2.18) | 0.00(%) |
Female | 16(21.1) | 292(45.1) | 0.3(0.18–0.58) | <0.001 | 16(21.1) | 16(21.1) | 1.0(0.46–2.18) | 0.00 (%) |
Comorbidity | ||||||||
DM | 3(3.9) | 86(13.3) | 0.3(0.08–0.87) | 0.019 | 3(3.9) | 3(3.9) | 1.0(0.20–5.12) | 0.00 (%) |
HTN | 12(15.8) | 221(34.2) | 0.4(0.19–0.68) | 0.001 | 12(15.8) | 12(15.8) | 1.0(0.42–2.39) | 0.00 (%) |
CAD | 1(1.3) | 22(3.4) | 0.4(0.05–2.85) | 0.498 | 1(1.3) | 1(1.3) | 1.0(0.06–16.29) | 0.00 (%) |
CHF | 0(0.0) | 4(0.6) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
CVA | 0(0.0) | 28(4.3) | — | 0.063 | 0(0.0) | 0(0.0) | — | — |
ESRD | 0(0.0) | 2(0.3) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
Outcome | ||||||||
GCS | 14.5 ± 2.4 | 14.2 ± 2.4 | — | 0.303 | 14.5 ± 2.4 | 14.2 ± 2.6 | — | 0.538 |
≤ 8 | 3(3.9) | 34(5.3) | 0.7(0.22–2.47) | 0.788 | 3(3.9) | 4(5.3) | 0.7(0.16–3.42) | 1.000 |
9–12 | 0(0.0) | 31(4.8) | — | 0.065 | 0(0.0) | 2(2.6) | — | 0.497 |
≥ 13 | 73(96.1) | 582(90.0) | 2.7(0.83–8.87) | 0.085 | 73(96.1) | 70(92.1) | 2.1(0.50–8.67) | 0.494 |
AIS ≥ 3, n (%) | ||||||||
Head/Neck | 9(11.8) | 166(25.7) | 0.4(0.19–0.80) | 0.008 | 9(11.8) | 14(18.4) | 0.6(0.24–1.47) | 0.258 |
Face | 0(0.0) | 1(0.2) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
Thorax | 4(5.3) | 33(5.1) | 1.0(0.36–3.00) | 1.000 | 4(5.3) | 3(3.9) | 1.4(0.29–6.26) | 1.000 |
Abdomen | 0(0.0) | 7(1.1) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
Extremity | 20(26.3) | 208(32.1) | 0.8(0.44–1.29) | 0.301 | 20(26.3) | 19(25.0) | 1.1(0.52–2.22) | 0.853 |
ISS, median (IQR) | 5.5(4–9) | 9(4–10) | — | 0.029 | 5.5(4–9) | 7(4–10) | — | 0.808 |
< 16 | 68(89.5) | 523(80.8) | 2.0(0.94–4.30) | 0.065 | 68(89.5) | 63(82.9) | 1.8(0.68–4.51) | 0.240 |
16–24 | 5(6.6) | 88(13.6) | 0.4(0.18–1.14) | 0.084 | 5(6.6) | 11(14.5) | 0.4(0.14–1.26) | 0.113 |
≥ 25 | 3(3.9) | 36(5.6) | 0.7(0.21–2.32) | 0.788 | 3(3.9) | 2(2.6) | 1.5(0.25–9.37) | 1.000 |
Hospital LOS (days) | 7.0 ± 9.5 | 8.9 ± 10.2 | — | 0.116 | 7.0 ± 9.5 | 6.7 ± 6.4 | — | 0.858 |
ICU | ||||||||
Patients, n (%) | 9(11.8) | 139(21.5) | 0.5(0.24–1.01) | 0.049 | 9(11.8) | 11(14.5) | 0.8(0.31–2.04) | 0.631 |
< 16 | 4(5.3) | 38(5.9) | 0.9(0.31–2.57) | 1.000 | 4(5.3) | 1(1.3) | 4.2(0.46–38.17) | 0.367 |
16–24 | 2(2.6) | 69(10.7) | 0.2(0.05–0.94) | 0.026 | 2(2.6) | 8(1.1) | 0.2(0.05–1.12) | 0.050 |
≥ 25 | 3(3.9) | 32(4.9) | 0.8(0.24–2.64) | 1.000 | 3(3.9) | 2(2.6) | 1.5(0.25–9.37) | 1.000 |
ICU LOS (days) | 11.0 ± 20.1 | 7.4 ± 9.5 | — | 0.612 | 11.0 ± 20.1 | 4.3 ± 2.3 | — | 0.346 |
Mortality | 4(5.3) | 24(3.7) | 1.4(0.49–4.27) | 0.524 | 4(5.3) | 3(3.9) | 1.3(0.30–5.96) | 0.706 |
Associated injuries at ED
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 |
Original cohort | Propensity score-matched cohort | |||||||
---|---|---|---|---|---|---|---|---|
Parameters | Helmet use Yes n = 76 | Helmet use No n = 647 |
Odds ratio
(95%)
|
P
| Helmet use Yes n = 76 | Helmet use No n = 76 |
Odds ratio
(95%)
|
P
|
Physiology at ED, n (%) | ||||||||
SBP < 90 mmHg | 1(1.3) | 13(2.0) | 0.7(0.08–5.04) | 1.000 | 1(1.3) | 1(1.3) | 1.0(0.06–16.29) | 1.000 |
Heart rate > 100 beats/min | 7(9.2) | 105(16.2) | 0.5(0.23–1.17) | 0.110 | 7(9.2) | 9(11.8) | 0.8(0.27–2.14) | 0.597 |
Respiratory rate < 10 or >29 /min | 0(0.0) | 5(0.8) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
Procedures at ED, n (%) | ||||||||
Cardiopulmonary resuscitation | 1(1.3) | 2(0.3) | 4.3(0.39–47.99) | 0.284 | 1(1.3) | 0(0.0) | — | 1.000 |
Intubation | 1(1.3) | 19(2.9) | 0.4(0.06–3.34) | 0.712 | 1(1.3) | 1(1.3) | 1.0(0.06–16.29) | 1.000 |
Chest tube insertion | 0(0.0) | 7(1.1) | — | 1.000 | 0(0.0) | 1(1.3) | — | 1.000 |
Blood transfusion | 2(2.6) | 23(3.6) | 0.7(0.17–3.17) | 1.000 | 2(2.6) | 1(1.3) | 2.0(0.18–22.84) | 1.000 |
Original cohort | Propensity score-matched cohort | |||||||
---|---|---|---|---|---|---|---|---|
Associated injuries | 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
|
Head trauma, n (%) | ||||||||
Neurologic deficit | 69(0.9) | 15(1.7) | 0.5(0.29–0.89) | 0.017 | 8(0.9) | 15(1.8) | 0.5(0.22–1.25) | 0.142 |
Cranial fracture | 444(5.7) | 175(20.3) | 0.2(0.20–0.29) | <0.001 | 53(6.2) | 173(20.2) | 0.3(0.19–0.36) | <0.001 |
Epidural hematoma (EDH) | 283(3.7) | 124(14.4) | 0.2(0.18–0.28) | <0.001 | 38(4.4) | 12(14.5) | 0.3(0.19–0.40) | <0.001 |
Subdural hematoma (SDH) | 647(8.4) | 245(28.4) | 0.2(0.20–0.27) | <0.001 | 87(10.2) | 245(28.6) | 0.3(0.22–0.37) | <0.001 |
Subarachnoid hemorrhage (SAH) | 770(10.0) | 228(26.4) | 0.3(0.26–0.36) | <0.001 | 91(10.6) | 227(26.5) | 0.3(0.25–0.43) | <0.001 |
Intracerebral hemorrhage (ICH) | 169(2.2) | 48(5.6) | 0.4(0.27–0.53) | <0.001 | 19(2.2) | 48(5.6) | 0.4(0.22–0.66) | <0.001 |
Cerebral contusion | 353(4.6) | 120(13.9) | 0.3(0.24–0.37) | <0.001 | 43(5.0) | 120(14.0) | 0.3(0.23–0.47) | <0.001 |
Cervical vertebra fracture | 60(0.8) | 15(1.7) | 0.4(0.25–0.78) | 0.004 | 4(0.5) | 15(1.8) | 0.3(0.09–0.80) | 0.011 |
Maxillofacial trauma, n (%) | ||||||||
Nasal fracture | 111(1.4) | 20(2.3) | 0.6(0.38–0.99) | 0.045 | 12(1.4) | 20(2.3) | 0.6(0.29–1.22) | 0.153 |
Maxillary fracture | 731(9.5) | 123(14.3) | 0.6(0.51–0.77) | <0.001 | 85(9.9) | 122(14.3) | 0.7(0.49–0.89) | 0.006 |
Mandibular fracture | 234(3.0) | 39(4.5) | 0.7(0.47–0.93) | 0.018 | 21(2.5) | 39(4.6) | 0.5(0.31–0.90) | 0.018 |
Original cohort | Propensity score-matched cohort | |||||||
---|---|---|---|---|---|---|---|---|
Associated injuries | Helmet use Yes n = 76 | Helmet use No n = 647 |
Odds ratio
(95%)
|
P
| Helmet use Yes n = 76 | Helmet use No n = 76 |
Odds ratio
(95%)
|
P
|
Head trauma, n (%) | ||||||||
Neurologic deficit | 0(0.0) | 3(0.5) | — | 1.000 | 0(0.0) | 0(0.0) | — | — |
Cranial fracture | 4(5.3) | 37(5.7) | 0.9(0.32–2.64) | 1.000 | 4(5.3) | 5(6.6) | 0.8(0.20–3.06) | 1.000 |
Epidural hematoma (EDH) | 1(1.3) | 34(5.3) | 0.2(0.03–1.78) | 0.163 | 1(1.3) | 5(6.6) | 0.2(0.02–1.66) | 0.209 |
Subdural hematoma (SDH) | 2(2.6) | 95(14.7) | 0.2(0.04–0.65) | 0.004 | 2(2.6) | 10(13.2) | 0.2(0.04–0.84) | 0.031 |
Subarachnoid hemorrhage (SAH) | 8(10.5) | 80(12.4) | 0.8(0.39–1.80) | 0.643 | 8(10.5) | 9(11.8) | 0.9(0.32–2.41) | 0.797 |
Intracerebral hemorrhage (ICH) | 1(1.3) | 16(2.5) | 0.5(0.07–4.02) | 1.000 | 1(1.3) | 0(0.0) | — | 1.000 |
Cerebral contusion | 3(3.9) | 45(7.0) | 0.6(0.17–1.81) | 0.319 | 3(3.9) | 4(5.3) | 0.7(0.16–3.42) | 1.000 |
Cervical vertebra fracture | 2(2.6) | 9(1.4) | 1.9(0.41–9.04) | 0.325 | 2(2.6) | 1(1.3) | 2.0(0.18–22.84) | 1.000 |
Maxillofacial trauma, n (%) | ||||||||
Nasal fracture | 1(1.3) | 5(0.8) | 1.7(0.20–14.85) | 0.488 | 1(1.3) | 2(2.6) | 0.5(0.04–5.56) | 1.000 |
Maxillary fracture | 9(11.8) | 34(5.3) | 2.4(1.11–5.27) | 0.035 | 9(11.8) | 4(5.3) | 2.4(0.71–8.22) | 0.147 |
Mandibular fracture | 2(2.6) | 9(1.4) | 1.9(0.41–9.04) | 0.325 | 2(2.6) | 0(0.0) | — | 0.497 |