Table 1 Baseline characteristics of ICCU admission
| Â | The 2-day average concentration of PM2.5 before ICCU admission | Â | ||
|---|---|---|---|---|
Characteristic | ≤36 μg/m3 | 37-63 μg/m3 | ≥64 μg/m3 | P value |
(N = 804) | (N = 773) | (N = 760) | ||
Age, yrs | 65.9 ± 14.0 | 64.9 ± 14.6 | 65.8 ± 13.9 | 0.316 |
Age ≥ 65 yrs | 473(58.8) | 434(56.1) | 446(58.7) | 0.938 |
Male, n (%) | 558(69.4) | 531(68.7) | 500(65.8) | 0.128 |
Source of admission, n (%) | ||||
 Department of Emergency | 503(62.6) | 536(69.3) | 565(74.3) | < 0.001 |
 General Ward of Cardiology | 254(31.6) | 201(26.0) | 165(21.7) | < 0.001 |
 Other Departments | 47(5.8) | 36(4.7) | 30(3.9) | 0.080 |
Type of admission, n (%) | ||||
 Medical | 176(21.9) | 164(21.2) | 178(23.4) | 0.474 |
 Scheduled procedure | 424(52.7) | 367(47.5) | 292(38.4) | < 0.001 |
 Unscheduled procedure | 204(25.4) | 242(31.3) | 290(38.2) | < 0.001 |
Vital signs | ||||
 Temperature, °C | 36.4 ± 0.8 | 36.4 ± 0.7 | 36.2 ± 2.7 | 0.208 |
 Respiratory rate, per min | 20.4 ± 3.5 | 20.3 ± 3.1 | 20.2 ± 4.5 | 0.745 |
 Heart rates, beats/min | 79.3 ± 21.5 | 79.8 ± 20.5 | 80.6 ± 22.4 | 0.467 |
 Systolic blood pressure, mmHg | 125.7 ± 45.0 | 124.0 ± 42.5 | 125.5 ± 45.8 | 0.717 |
 Diastolic blood pressure, mmHg | 72.6 ± 15.8 | 72.7 ± 15.8 | 72.6 ± 17.4 | 0.988 |
Charlson Comorbidity Index | 2.3 ± 1.8 | 2.3 ± 1.9 | 2.4 ± 1.9 | 0.198 |
Oxford Acute Severity of Illness Score | 21.5 ± 9.8 | 22.4 ± 10.7 | 23.7 ± 10.7 | < 0.001 |
Cardiovascular comorbidities, n (%) | ||||
Ischemic heart disease | 578(71.9) | 587(75.9) | 548(72.1) | 0.898 |
 ACS | 434(54.0) | 468(60.5) | 469(61.7) | 0.002 |
  STEMI | 214(26.6) | 264(34.2) | 270(35.5) | < 0.001 |
  NSTEMI | 114(14.2) | 123(15.9) | 120(15.8) | 0.371 |
  UA | 106(13.2) | 81(10.5) | 79(10.4) | 0.080 |
 SIHD | 137(17.0) | 112(14.5) | 75(9.9) | < 0.001 |
 MI mechanical complications | 14(1.7) | 10(1.3) | 13(1.7) | 0.951 |
Hypertension | 432(53.7) | 391(50.6) | 388(51.1) | 0.283 |
Myocardial disease | 70(8.7) | 65(8.4) | 64(8.4) | 0.838 |
Valvar heart disease | 298(37.1) | 285(36.9) | 268(35.3) | 0.463 |
Heart failure | 472(58.7) | 458(59.2) | 460(60.5) | 0.465 |
NYHA functional classification | ||||
 I | 260(32.3) | 250(32.3) | 266(35.0) | 0.268 |
 II-III | 291(36.2) | 266(34.4) | 264(34.7) | 0.541 |
 IV | 167(20.8) | 179(23.2) | 180(23.7) | 0.166 |
Cardiac shock | 53(6.6) | 64(8.3) | 59(7.8) | 0.372 |
Cardiac arrest | 45(5.6) | 52(6.7) | 67(8.8) | 0.013 |
Atrial arrhythmia | 140(17.4) | 130(16.8) | 142(18.7) | 0.517 |
Ventricular arrhythmia | 63(7.8) | 45(5.8) | 51(6.7) | 0.366 |
Bradycardia | 92(11.4) | 90(11.6) | 68(8.9) | 0.114 |
Congenital heart disease | 13(1.6) | 13(1.7) | 14(1.8) | 0.733 |
Pericardial disease | 10(1.2) | 9(1.2) | 8(1.1) | 0.724 |
Aortic disease | 6(0.7) | 13(1.7) | 14(1.8) | 0.065 |
 Acute aortic syndrome | 2(0.2) | 3(0.4) | 6(0.8) | 0.120 |
Cerebrovascular disease | 75(9.3) | 55(7.1) | 78(10.3) | 0.539 |
 Acute stroke/TIA | 9(1.1) | 5(0.6) | 12(1.6) | 0.400 |
Peripheral arterial disease | 18(2.2) | 14(1.8) | 18(2.4) | 0.869 |
Venous thromboembolism | 11(1.4) | 7(0.9) | 11(1.4) | 0.901 |
Noncardiovascular comorbidities, n (%) | ||||
Tobacco abuse | 279(34.7) | 275(35.6) | 245(32.2) | 0.312 |
Alcohol abuse | 56(7.0) | 70(9.1) | 57(7.5) | 0.676 |
Diabetes mellitus | 237(29.5) | 210(27.2) | 212(27.9) | 0.479 |
Chronic kidney disease | 155(19.3) | 127(16.4) | 153(20.1) | 0.688 |
Hypercholesterolemia | 118(14.7) | 122(15.8) | 139(18.3) | 0.054 |
Chronic lung disease | 120(14.9) | 102(13.2) | 101(13.3) | 0.344 |
Malignancy | 30(3.7) | 25(3.2) | 23(3.0) | 0.436 |
Thyroid Disease | 17(2.1) | 8(1.0) | 20(2.6) | 0.479 |
Connective tissue disease | 7(0.9) | 9(1.2) | 10(1.3) | 0.400 |
Gout | 23(2.9) | 29(3.8) | 19(2.5) | 0.695 |
Moderate/severe anemia | 76(9.5) | 67(8.7) | 75(10.0) | 0.802 |
Hepatic dysfunction | 56(7.0) | 75(9.7) | 70(9.2) | 0.109 |
Dyskalemia | 216(26.9) | 232(30.0) | 228(30.0) | 0.168 |
Pneumonia/LRTI | 214(26.6) | 217(28.1) | 231(30.4) | 0.908 |
Major acute nonCV critical illnesses | 147(18.3) | 168(21.7) | 193(25.4) | 0.001 |
 Acute respiratory failure | 95(11.8) | 114(14.7) | 133(17.5) | 0.001 |
 Acute kidney injury | 96(11.9) | 107(13.8) | 118(15.5) | 0.039 |
 Sepsis | 29(3.6) | 31(4.0) | 38(5.0) | 0.171 |
 Gastrointestinal hemorrhage | 22(2.7) | 24(3.1) | 32(4.2) | 0.106 |