Table 2: Cox proportional hazard ratios, 95% confidence intervals, and p-values for all variables included in the models of mortality at 4 hours, 24 hours, and 30 days.

HR = Hazard Ratio; GCS = Glasgow Coma Scale; ISS = Injury Severity Score. For variables with groups in parentheses, the former was compared with the latter (the reference).

Variable	HR (95% CI), 4-hour mortality	P-value, 4-hour mortality	HR (95% CI), 24-hour mortality	P-value, 24-hour mortality	HR (95% CI), 30-day mortality	P-value, 30-day mortality
Received Plasma in 4 hours	0.610 (0.430-0.864)	0.005	0.894 (0.706-1.131)	0.350	1.132 (0.961 - 1.334)	0.138
Received blood product transfusion in 4 hours
Red blood cells	2.190 (1.524-3.147)	< 0.001	2.068 (1.634-2.617)	< 0.001	1.458 (1.255 - 1.693)	< 0.001
Platelets	0.892 (0.598-1.330)	0.575	1.004 (0.789-1.279)	0.972	1.149 (0.980 - 1.347)	0.088
Whole blood	0.999 (0.629-1.586)	0.995	0.917 (0.662-1.270)	0.600	1.117 (0.900 - 1.387)	0.317
Total transfusion requirement in 4 hours	1.000 (1.000-1.000)	0.696	1.000 (1.000-1.000)	0.718	1.000 (1.000 - 1.000)	0.821
Age	0.936 (0.908-0.965)	< 0.001	0.976 (0.958-0.995)	0.015	0.977 (0.966 - 0.988)	< 0.001
Sex (Female vs. Male)	0.937 (0.683-1.287)	0.688	0.891 (0.742-1.071)	0.218	0.929 (0.828 - 1.043)	0.215
Mechanism of injury
Blunt	Reference	n/a	Reference	n/a	Reference	n/a
Penetrating	6.873 (5.044-9.366)	< 0.001	4.477 (3.620-5.537)	< 0.001	3.779 (3.307 - 4.318)	< 0.001
Mixed	3.754 (0.754-18.697)	0.106	2.983 (1.178-7.552)	0.021	1.744 (0.805 - 3.778)	0.158
Other	0.987 (0.534-1.823)	0.967	1.334 (0.991-1.798)	0.058	1.293 (1.061 - 1.576)	0.011
Interfacility (Transferred vs. Not transferred)	0.685 (0.499-0.940)	0.019	0.823 (0.685-0.989)	0.037	0.866 (0.777 - 0.964)	0.009
Shock (Present vs. Absent)	1.222 (0.911-1.640)	0.181	1.513 (1.258-1.820)	< 0.001	1.468 (1.310 - 1.645)	< 0.001
Total GCS	0.628 (0.549-0.720)	< 0.001	0.667 (0.628-0.707)	< 0.001	0.686 (0.666 - 0.707)	< 0.001
ISS	1.022 (1.011-1.034)	< 0.001	1.018 (1.010-1.027)	< 0.001	1.017 (1.013 - 1.022)	< 0.001
Pediatric trauma center level verification
Level 1	Reference	n/a	Reference	n/a	Reference	n/a
Level 2	0.947 (0.624-1.438)	0.798	0.979 (0.716-1.337)	0.892	1.015 (0.864 - 1.193)	0.856
Level 3	1.286 (0.964-1.717)	0.087	1.505 (1.227-1.847)	< 0.001	1.304 (1.154 - 1.472)	< 0.001
Insurance Status, no (%)
Governmental	Reference	n/a	Reference	n/a	Reference	n/a
Private	1.162 (0.846-1.597)	0.354	1.180 (0.991-1.404)	0.063	1.021 (0.915 - 1.139)	0.707
Other	2.134 (1.554-2.930)	<0.001	1.956 (1.569-2.438)	< 0.001	1.749 (1.501 - 2.037)	< 0.001