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Table 1 Characteristics of the patients before and after propensity score matching (All variables)

From: Physician-led prehospital management is associated with reduced mortality in severe blunt trauma patients: a retrospective analysis of the Japanese nationwide trauma registry

Variables Overall study cohort Propensity score–matched cohort
Physician-led group
(n = 2976)
Paramedic-led group
(n = 27,575)
ASMD Physician-led group
(n = 2690)
Paramedic-led group
(n = 10,760)
ASMD
Age, years, median (IQR) 62 (42, 74) 63 (43, 75) 0.011 62 (41, 74) 62 (43, 75) 0.024
Females, n (%) 855 (28.7) 8091 (29.3) 0.013 760 (28.3) 3167 (29.4) 0.026
Year of injury, n (%)    0.136    0.087
 2009–2013 1089 (36.6) 10.768 (39.0)   1086 (40.4) 4081 (37.9)  
 2014–2019 1887 (63.4) 16,807 (61.0)   1604 (59.6) 6679 (62.1)  
Time of injury, n (%)    0.332    0.008
 Daytime 2285 (76.8) 17,019 (61.7)   2017 (75.0) 8074 (75.0)  
 Nighttime 691 (23.2) 10,556 (38.3)   673 (25.0) 2686 (25.0)  
Mechanism of injury, n (%)    0.357    0.041
 Traffic accident 1662 (55.8) 14,285 (51.8)   1482 (55.1) 5948 (55.3)  
 Fall from height 522 (17.5) 3475 (12.6)   455 (16.9) 1852 (17.2)  
 Fall (others) 552 (18.5) 8344 (30.3)   541 (20.1) 2180 (20.3)  
 Others 240 (8.1) 1471 (5.3)   212 (7.9) 780 (7.2)  
Vital signs at the scene of injury, median (IQR)
 Systolic blood pressure, mmHg 132 (110, 159) 135 (112, 160) 0.056 134 (113, 156) 134 (112, 158) 0.032
 Heart ratea, beats/min 84 (72, 100) 84 (72, 98) 0.071 84 (70, 100) 84 (72, 100) 0.012
 Respiratory rate, breaths/min 24 (19, 28) 20 (18, 24) 0.167 21 (18, 26) 21 (18, 26) < 0.001
Japan Coma Scale at the scene of injury, n (%)    0.226    0.020
 0 (alert) 774 (26.0) 7855 (28.5)   721 (26.8) 2898 (26.9)  
 300 (deep coma) 374 (12.6) 2484 (9.0)   303 (11.3) 1263 (1.7)  
The highest score of AIS, median (IQR)
 Heada 3 (0, 4) 3 (0, 4) 0.007 3 (0, 4) 3 (0, 4) 0.017
 Facea 0 (0, 0) 0 (0, 0) 0.044 0 (0, 0) 0 (0, 0) 0.026
 Necka 0 (0, 0) 0 (0, 0) 0.014 0 (0, 0) 0 (0, 0) 0.036
 Chesta 3 (0, 4) 0 (0, 3) 0.251 3 (0, 4) 2 (0, 4) 0.048
 Abdomena 0 (0, 0) 0 (0, 0) 0.12 0 (0, 0) 0 (0, 0) 0.017
 Spinea 0 (0, 2) 0 (0, 2) 0.027 0 (0, 2) 0 (0, 2) 0.005
 Upper extremitiesa 0 (0, 2) 0 (0, 1) 0.124 0 (0, 2) 0 (0, 2) 0.036
 Pelvis and lower extremitiesa 0 (0, 2) 0 (0, 2) 0.166 0 (0, 2) 0 (0, 2) 0.044
 Surfacea 0 (0, 0) 0 (0, 0) 0.02 0 (0, 0) 0 (0, 0) < 0.001
ISS, median (IQR) 25 (18, 33) 21 (17, 27) 0.279 24 (17, 30) 24 (17, 29) 0.007
Prehospital time-course, min, median (IQR)
 Injury to physician contacta 40 (30, 55) 46 (35, 61) 0.331 39 (29, 53) 53 (39, 72) 0.719
 Injury to ED arrival 56 (42, 73) 44 (34, 58) 0.477 54 (41, 68) 50 (38, 70) 0.006
Transporter, n (%)    1.741    1.478
 Air ambulancea 971 (32.6) 1430 (5.2)   829 (30.8) 1078 (10.0)  
 Ground ambulancea 2005 (67.4) 26,113 (94.7)   1861 (69.2) 9667 (89.8)  
 Othersa 0 (0) 32 (0.1)   0 (0) 15 (0.1)  
Intubation in the prehospital settingsa, n (%) 248 (8.4) 250 (0.9) 0.361 199 (7.5) 192 (1.8) 0.271
  1. Abbreviations: ASMD Absolute standardized mean difference, IQR Interquartile range, AIS Abbreviated injury scale, ISS Injury severity score, ED Emergency department
  2. aThese variables were not included in the model for propensity score estimation