Table 1.
Characteristics and outcomes of acute coronary syndrome cases, before and after dispatch with the optimized medical priority dispatch system (MPDS), total cases (N=9806), and propensity score–matched cases.
| Characteristics and Outcomes | Total cases | Propensity score–matched casesa (n=8144) | Standardized mean difference | |||||
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Before MPDS (n=3561) | After MPDS (n=6245) | P value | Before MPDS (n=2715) | After MPDS (n=5429) | P value |
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| Age (years), mean (SD) | 66.2 (13.4) | 65.6 (12.9) | .03 | 62.6 (13.3) | 65.2 (12.9) | .25 | 0.02 | |
| Male, n (%) | 2588 (72.7) | 4414 (70.7) | .04 | 2008 (74.0) | 3888 (71.6) | .03 | 0.05 | |
| Living in a provincial capital city, n (%) | 1168 (32.4) | 2587 (41.4) | <.001 | 1027 (37.8) | 2251 (41.5) | .002 | 0.20 | |
| Call time of the day, n (%) | .10 |
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.07 | 0.06 | |||
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12-5:59 AM | 651 (18.3) | 1252 (20.0) |
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491 (18.1) | 1089 (20.1) |
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6-11:59 AM | 1154 (32.4) | 2030 (32.5) |
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860 (31.7) | 1765 (32.5) |
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12-5:59 PM | 875 (24.6) | 1518 (24.3) |
|
690 (25.4) | 1324 (24.4) |
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6-11:59 PM | 881 (24.7) | 1445 (23.1) |
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674 (24.8) | 1251 (23.0) |
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| Call on weekday, n (%) | 2516 (70.7) | 4505 (72.1) | .12 | 1914 (70.5) | 3925 (72.3) | .09 | 0.04 | |
| Precall chest pain, n (%)b | .004 |
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.21 | 0.04 | |||
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Persistent chest pain | 2233 (69.1) | 4221 (72.1) |
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1954 (72.0) | 3960 (72.9) |
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Intermittent chest pain | 837 (25.9) | 1336 (22.8) |
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644 (23.7) | 1206 (22.2) |
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Eased chest pain | 163 (5.0) | 299 (5.1) |
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117 (4.3) | 263 (4.8) |
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| Type of acute coronary syndrome, n (%) | <.001 |
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.21 | 0.06 | |||
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ST-elevation myocardial infarction | 2057 (57.8) | 3928 (62.9) |
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1703 (62.7) | 3508 (64.6) |
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Non–ST-elevation myocardial infarction | 627 (17.6) | 1084 (17.4) |
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554 (20.4) | 971 (17.9) |
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Unstable angina pectoris | 877 (24.6) | 1233 (19.7) |
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458 (16.9) | 950 (17.5) |
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| Killip class, n (%)b | <.001 |
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.05 | 0.07 | |||
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I | 2333 (72.8) | 4495 (77.8) |
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2073 (76.4) | 4269 (78.6) |
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II-III | 625 (19.5) | 876 (15.2) |
|
440 (16.2) | 814 (15.0) |
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IV | 245 (7.6) | 408 (7.1) |
|
202 (7.4) | 346 (6.4) |
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| Onset-to-call time (minutes), median (IQR) | 54.0 (18.0-124.0) | 56.0 (20.0-124.0) | .48 | 56.0 (20.0-128.0) | 56.0 (20.0-124.0) | .87 | 0.03 | |
| Call-to-EMSc arrival time (min), median (IQR) | 18.0 (12.0-30.0) | 16.0 (10.0-26.0) | <.001 | 20.0 (12.0-30.0) | 16.0 (10.0-26.0) | <.001 | N/Ad | |
| EMS arrival-to-door time (minutes), median (IQR) | 20.0 (12.0-30.0) | 20.0 (12.0-28.0) | <.001 | 20.0 (12.0-30.0) | 20.0 (12.0-30.0) | .31 | N/A | |
| Total EMS time (call-to-door; minutes), median (IQR) | 40.0 (28.0-56.0) | 38.0 (28.0-52.0) | <.001 | 40.0 (29.0-58.0) | 38.0 (28.0-52.0) | <.001 | N/A | |
aPropensity score matched for age, gender, city level, call time of the day, call on weekday, precall chest pain symptoms, type of acute coronary syndrome, Killip class, and onset-to-call time.
bMissing cases were excluded when comparing the precall chest pain symptoms and Killip class between the 2 groups.
cEMS: emergency medical service.
dN/A: not applicable.