Table 2.

Crude Hazards at 15-min Intervals after Injury, for Patients Who Have Arrived at a Hospital with Detectable Vital Signs

Time in minutes (tp + th)	Patients at risk S	Admissions a	Deaths d	Hazard d/S
0– 14	0	640	0	-
15– 29	640	15,873	11	0.0172
30– 44	16,502	29,594	77	0.0047
45– 59	46,019	20,435	74	0.0016
60– 74	66,380	10,100	87	0.0013
75– 89	76,373	4,523	98	0.0013
90–104	80,818	2,069	122	0.0015
105–119	82,765	941	97	0.0012
120–134	83,609	383	86	0.0010
135–149	83,906	273	103	0.0012
150–164	84,076	124	75	0.0009
165–179	84,125	93	88	0.0010
180–194	84,130	60	86	0.0010
195–209	84,104	37	85	0.0010
210–224	84,056	37	81	0.0010
225–239	84,102	23	77	0.0009
240–254	83,958	19	76	0.0009
255–269	83,901	12	61	0.0007
270–284	83,852	13	56	0.0007
285–299	83,809	7	57	0.0007
300–314	83,759	9	41	0.0005
315–329	83,727	13	44	0.0005
330–344	83,696	10	48	0.0006
345–359	83,658	3	49	0.0006
360–374	83,612	9	46	0.0006
375–389	83,575	5	37	0.0004
390–404	85,327	3	31	0.0004
405–419	83,515	5	17	0.0002
420–434	83,503	5	32	0.0004
435–449	83,476	5	34	0.0004
450–464	83,447	2	32	0.0004
465–479	83,417	2	33	0.0004

At the beginning or each time interval i, the number or patients at risk S_i may be calculated as S_i-1 + a_i-1 − d_i-1. The hazard is the rate of death among the patients at risk during the specified time interval. Time after injury is calculated as prehospital time (t_p) plus hospital time (t_h). HR models described elsewhere in this article calculate the hazard for each minute rather than for 15-minute intervals.