Table 1.
Baseline characteristics of the patients
| Characteristic | Before propensity score weighting | After propensity score weighting | ||||
|---|---|---|---|---|---|---|
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| Off-hours group (n = 3,119) | On-hours group (n = 2,245) | p value | Off-hours group (n = 4,758) | On-hours group (n = 4,773) | p value | |
| Male patients | 2,480 (79.5) | 1,735 (77.3) | 0.050 | 3,726 (78.3) | 3,733 (78.2) | 0.943 |
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| Age, yr | 61.41 ± 12.64 | 63.19 ± 12.66 | < 0.001 | 61.94 ± 12.70 | 62.12 ± 12.59 | 0.626 |
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| Age ≥ 65 years | 1,266 (40.6) | 1,063 (47.3) | < 0.001 | 2,039 (42.9) | 2,048 (42.9) | 0.974 |
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| First medical contact | < 0.001 | 0.975 | ||||
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| Emergency medical service | 681 (21.8) | 343 (15.3) | 889 (18.7) | 885 (18.6) | ||
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| No emergency medical service | 2,438 (78.2) | 1,902 (84.7) | 3,869 (81.3) | 3,888 (81.4) | ||
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| PCI-capable center | 900 (28.9) | 598 (29.6) | 1,310 (27.5) | 1,329 (27.8) | ||
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| PCI-incapable center | 1,538 (49.3) | 1,304 (58.1) | 2,559 (53.8) | 2,559 (53.6) | ||
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| Total ischemic time ≥ 12 hr | 418 (13.4) | 505 (22.5) | < 0.001 | 799 (16.8) | 802 (16.8) | 0.983 |
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| Total ischemic time, hr | 9.56 ± 32.70 | 16.50 ± 53.98 | < 0.001 | 10.59 ± 31.68 | 13.06 ± 48.29 | 0.036 |
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| Onset-to-door time, min | 444.79 ± 1,723.64 | 835.97 ± 2,554.58 | < 0.001 | 506.80 ± 1,648.81 | 638.12 ± 2,166.64 | 0.017 |
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| Onset-to-door time ≥ 4 hr | 895 (28.7) | 888 (39.6 ) | < 0.001 | 1,566 (32.9) | 1,569 (32.9) | 0.978 |
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| Door-to-balloon time, min | 158.23 ± 752.62 | 182.89 ± 1709.53 | 0.522 | 157.66 ± 764.92 | 174.12 ± 1,655.81 | 0.658 |
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| Door-to-balloon time ≥ 90 min | 375 (12.0) | 238 (10.6) | 0.106 | 525 (11.0) | 530 (11.1) | 0.941 |
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| Pulse pressure, mmHg | 49.70 ± 16.10 | 49.88 ± 16.39 | 0.688 | 49.67 ± 15.78 | 49.58 ± 16.41 | 0.848 |
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| Pulse pressure ≥ 40 mmHg | 2,498 (81.1) | 1,842 (83.3) | 0.037 | 3,920 (82.4) | 3,935 (82.4) | 0.959 |
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| Killip functional classification | 0.341 | 0.732 | ||||
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| Killip functional class I | 2,491 (79.9) | 1,795 (80.0) | 3,850 (80.9) | 3,843 (80.5) | ||
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| Killip functional class II | 230 (7.4) | 189 (8.4) | 374 (7.9) | 391 (8.2) | ||
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| Killip functional class III | 174 (5.6) | 110 (4.9) | 278 (5.8) | 254 (5.3) | ||
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| Killip functional class IV | 224 (7.2) | 151 (6.7) | 256 (5.4) | 284 (6.0) | ||
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| Killip functional class III–IV | 398 (12.8) | 261 (11.6) | 0.212 | 534 (11.2) | 538 (11.3) | 0.953 |
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| BMI, kg/m2 | 24.18 ± 3.20 | 24.04 ± 3.28 | 0.117 | 24.09 ± 3.22 | 24.12 ± 3.30 | 0.783 |
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| BMI ≥ 25 kg/m2 | 1,108 (36.5) | 745 (34.0) | 0.054 | 1,680 (35.3) | 1,681 (35.2) | 0.948 |
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| Previous history | ||||||
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| Hypertension | 1,411 (45.2) | 1,034 (46.1) | 0.552 | 2,165 (45.5) | 2,180 (45.7) | 0.906 |
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| Diabetes mellitus | 706 (22.6) | 552 (24.6) | 0.096 | 1,106 (23.2) | 1,106 (23.2) | 0.958 |
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| Dyslipidemia | 336 (10.8) | 209 (9.3) | 0.080 | 484 (10.2) | 484 (10.1) | 0.970 |
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| Prior angina | 200 (6.4) | 108 (4.8) | 0.013 | 273 (5.7) | 276 (5.8) | 0.963 |
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| Prior heart failure | 19 (0.6) | 17 (0.8) | 0.514 | 33 (0.7) | 32 (0.7) | 0.948 |
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| Prior CVA | 151 (4.9) | 108 (4.8) | 0.954 | 228 (4.8) | 229 (4.8) | 0.990 |
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| Smoking | 1,989 (65.6) | 1,380 (63.0) | 0.047 | 3,056 (64.2) | 3,066 (64.2) | 0.994 |
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| Family history of CAD | 212 (7.0) | 124 (5.7) | 0.054 | 306 (6.4) | 308 (6.5) | 0.987 |
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| CrCl, mL/min/1.73 m2 | 82.79 ± 38.03 | 79.38 ± 39.61 | 0.002 | 81.86 ± 38.17 | 81.19 ± 39.15 | 0.558 |
|
| ||||||
| CrCl < 60 mL/min/1.73 m2 | 777 (25.6) | 666 (30.3) | < 0.001 | 1,297 (27.3) | 1,301 (27.3) | 0.995 |
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| LVEF, % | 50.88 ± 9.94 | 50.43 ± 10.22 | 0.109 | 50.87 ± 9.93 | 50.77 ± 10.11 | 0.733 |
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| LVEF < 40% | 357 (11.7) | 278 (12.7) | 0.304 | 559 (11.8) | 558 (11.7) | 0.953 |
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| Discharge medications | ||||||
|
| ||||||
| Aspirin | 3,117 (99.9) | 2,245 (100.0) | 0.513 | 4,758 (100.0) | 4,773 (100.0) | - |
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| P2Y12 inhibitor | 3,111 (99.7) | 2,243 (99.9) | 0.209 | 4,749 (99.8) | 4,763 (99.8) | 0.965 |
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| Calcium channel blocker | 112 (3.6) | 72 (3.2) | 0.446 | 158 (3.3) | 161 (3.4) | 0.941 |
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| Beta-blocker | 2,748 (88.1) | 1,971 (87.8) | 0.731 | 4,191 (88.1) | 4,200 (88.0) | 0.921 |
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| ACE inhibitor or ARB | 2,542 (81.5) | 1,848 (82.3) | 0.445 | 3,931 (82.6) | 3,946 (82.7) | 0.969 |
|
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| Statin | 2,969 (95.2) | 2,151 (95.8) | 0.281 | 4,550 (95.6) | 4,563 (95.6) | 0.976 |
Values are presented as number (%) or mean ± standard deviation.
PCI, percutaneous coronary intervention; BMI, body-mass index; CVA, cerebrovascular accident; CAD, coronary artery disease; CrCl, creatinine clearance; LVEF, left ventricular ejection fraction; ACE, angiotensin-converting enzyme; ARB, angiotensin receptor blocker.