Table 2.

Unadjusted and Propensity Score Analyses of Health Outcomes, by Ambulance Service Level^*

Outcome	BLS (95% CI), %	ALS (95% CI), %	Difference (95% CI), percentage points
Major trauma
Sample, n	30 919	48 768	–
Unadjusted outcomes
Survival to discharge	95.5 (95.3 to 95.7)	90.1 (89.8 to 90.3)	5.4 (5.1 to 5.8)
Survival to 30 d	89.2 (88.9 to 89.5)	83.1 (82.8 to 83.5)	6.1 (5.6 to 6.5)
Survival to 90 d	81.7 (81.3 to 82.2)	76.8 (76.5 to 77.2)	4.9 (4.3 to 5.5)
Poor neurologic performance	0.17 (0.12 to 0.21)	0.43 (0.37 to 0.49)	−0.26 (−0.34 to −0.19)
Adjusted outcomes
Survival to discharge	95.5 (95.3 to 95.8)	90.5 (90.2 to 90.8)	5.0 (4.6 to 5.4)
Survival to 30 d	89.4 (89.0 to 89.7)	83.1 (82.7 to 83.5)	6.3 (5.7 to 6.8)
Survival to 90 d	82.3 (81.9 to 82.8)	76.2 (75.8 to 76.7)	6.1 (5.4 to 6.8)
Survival to 1 y	70.0 (69.4 to 70.6)	64.9 (64.4 to 65.5)	5.1 (4.2 to 5.9)
Survival to 2 y	59.3 (58.5 to 60.0)	54.9 (54.2 to 55.5)	4.4 (3.4 to 5.4)
Poor neurologic performance	0.16 (0.12 to 0.21)	0.39 (0.32 to 0.45)	−0.22 (−0.31 to −0.14)
Stroke
Sample, n	19 985	100 004	–
Unadjusted outcomes
Survival to discharge	94.6 (94.3 to 95.0)	91.9 (91.8 to 92.1)	2.7 (2.4 to 3.1)
Survival to 30 d	84.4 (83.9 to 84.9)	79.3 (79.1 to 79.6)	5.1 (4.5 to 5.6)
Survival to 90 d	76.6 (76.0 to 77.2)	72.2 (72.0 to 72.5)	4.4 (3.7 to 5.0)
Poor neurologic performance	0.23 (0.16 to 0.30)	0.46 (0.41 to 0.50)	−0.23 (−0.30 to −0.15)
Adjusted outcomes
Survival to discharge	94.9 (94.6 to 95.2)	91.2 (90.9 to 91.4)	3.8 (3.3 to 4.2)
Survival to 30 d	84.8 (84.3 to 85.3)	77.8 (77.5 to 78.2)	7.0 (6.3 to 7.6)
Survival to 90 d	77.2 (76.6 to 77.8)	70.3 (69.9 to 70.7)	7.0 (6.2 to 7.7)
Survival to 1 y	62.8 (62.1 to 63.6)	57.4 (56.9 to 57.8)	5.5 (4.6 to 6.4)
Survival to 2 y	51.6 (50.7 to 52.5)	47.3 (46.7 to 47.8)	4.3 (3.3 to 5.4)
Poor neurologic performance	0.21 (0.15 to 0.28)	0.51 (0.44 to 0.57)	−0.29 (−0.39 to −0.20)
AMI
Sample, n	14 434	100 035	–
Unadjusted outcomes
Survival to discharge	87.9 (87.4 to 88.5)	87.6 (87.4 to 87.8)	0.3 (−0.3 to 0.9)
Survival to 30 d	77.5 (76.8 to 78.2)	80.3 (80.0 to 80.5)	−2.8 (−3.5 to −2.1)
Survival to 90 d	68.6 (67.8 to 69.3)	73.6 (73.3 to 73.9)	−5.1 (−5.9 to −4.3)
Poor neurologic performance	0.71 (0.58 to 0.85)	2.07 (1.98 to 2.15)	−1.35 (−1.51 to −1.19)
Adjusted outcomes
Survival to discharge	88.4 (87.9 to 89.0)	87.3 (87.0 to 87.6)	1.1 (0.5 to 1.8)
Survival to 30 d	78.2 (77.5 to 78.9)	78.5 (78.1 to 78.8)	−0.3 (−1.1 to 0.5)
Survival to 90 d	69.5 (68.8 to 70.3)	70.5 (70.1 to 70.9)	−1.0 (−1.9 to −0.1)
Survival to 1 y	55.2 (54.3 to 56.0)	57.2 (56.7 to 57.7)	−2.0 (−3.0 to −1.1)
Survival to 2 y	44.1 (43.1 to 45.2)	45.9 (45.4 to 46.5)	−1.8 (−2.9 to −0.6)
Poor neurologic performance	0.73 (0.58 to 0.87)	1.61 (1.50 to 1.71)	−0.88 (−1.06 to −0.70)
Respiratory failure
Sample, n	9502	73 028	–
Unadjusted outcomes
Survival to discharge	77.0 (76.1 to 77.8)	75.2 (74.9 to 75.5)	1.8 (0.9 to 2.7)
Survival to 30 d	66.4 (65.4 to 67.3)	64.3 (63.9 to 64.6)	2.1 (1.1 to 3.1)
Survival to 90 d	55.6 (54.6 to 56.6)	55.4 (55.0 to 55.7)	0.2 (−0.9 to 1.2)
Poor neurologic performance	2.39 (2.08 to 2.70)	5.86 (5.69 to 6.03)	−3.47 (−3.83 to −3.12)
Adjusted outcomes
Survival to discharge	77.5 (76.7 to 78.4)	73.6 (73.1 to 74.1)	3.9 (3.0 to 4.9)
Survival to 30 d	66.9 (66.0 to 67.9)	62.5 (61.9 to 63.0)	4.5 (3.4 to 5.6)
Survival to 90 d	56.5 (55.4 to 57.5)	52.8 (52.3 to 53.3)	3.7 (2.5 to 4.8)
Survival to 1 y	40.1 (39.0 to 41.3)	37.5 (36.9 to 38.0)	2.7 (1.4 to 3.9)
Survival to 2 y	29.1 (28.0 to 30.3)	27.9 (27.3 to 28.5)	1.2 (−0.1 to 2.5)
Poor neurologic performance	2.39 (2.07 to 2.71)	5.50 (5.26 to 5.73)	−3.10 (−3.50 to −2.71)

ALS = advanced life support; AMI = acute myocardial infarction; BLS = basic life support.

^*Unless otherwise indicated, estimates are adjusted by propensity score–based balancing weights. Estimates for survival to 1 y used data from 2006 to 2010, and estimates for survival to 2 y used data from 2006 to 2009.