Table 1.
Baseline characteristics of participants by quartiles of the systemic immune-inflammation index (N = 1181).
| Variables | Total | Quartiles of the systemic immune-inflammation index (109/L) | P value | |||
|---|---|---|---|---|---|---|
| Q1 | Q2 | Q3 | Q4 | |||
| <667.5 | 667.5–1243.2 | 1243.2–2242 | >2242 | |||
| Participants (N) | 1181 | 295 | 295 | 295 | 296 | |
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| Characteristics | ||||||
| Age, years | 69.1 ± 15.6 | 71.2 ± 15.1 | 69.3 ± 16.5 | 67.7 ± 15.0 | 68.2 ± 15.8 | 0.035 |
| Female, n (%) | 581 (49.2) | 144 (48.8) | 146 (49.5) | 151 (51.2) | 140 (47.3) | 0.82 |
| Heart rate | 83.7 ± 18.7 | 78.8 ± 16.5 | 81.7 ± 17.7 | 84.4 ± 19.3 | 89.7 ± 19.2 | <0.001 |
| MAP, mmHg | 76.3 ± 19.3 | 75.8 ± 18.6 | 75.2 ± 18.8 | 78.2 ± 21.0 | 76.2 ± 18.6 | 0.282 |
| Respiratory rate | 19.2 ± 5.6 | 18.3 ± 5.0 | 18.5 ± 4.8 | 19.7 ± 6.1 | 20.4 ± 6.0 | <0.001 |
| Temperature (°C) | 36.8 ± 0.8 | 36.7 ± 0.7 | 36.8 ± 0.7 | 36.8 ± 0.7 | 36.8 ± 0.9 | 0.117 |
| SPO2% | 97.2 ± 3.7 | 97.8 ± 2.7 | 97.3 ± 3.8 | 96.9 ± 3.8 | 96.8 ± 4.2 | 0.003 |
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| Comorbidities, n (%) | ||||||
| Hypertension, n (%) | 602 (51.0) | 152 (51.5) | 158 (53.6) | 145 (49.2) | 147 (49.7) | 0.701 |
| Hyperlipidemia, n (%) | 613 (51.9) | 170 (57.6) | 165 (55.9) | 160 (54.2) | 118 (39.9) | <0.001 |
| Atrial fibrillation, n (%) | 450 (38.1) | 98 (33.2) | 115 (39) | 119 (40.3) | 118 (39.9) | 0.252 |
| Myocardial infarct, n (%) | 200 (16.9) | 43 (14.6) | 50 (16.9) | 52 (17.6) | 55 (18.6) | 0.607 |
| CHF, n (%) | 300 (25.4) | 68 (23.1) | 69 (23.4) | 86 (29.2) | 77 (26) | 0.291 |
| PVD, n (%) | 134 (11.3) | 36 (12.2) | 33 (11.2) | 31 (10.5) | 34 (11.5) | 0.933 |
| Dementia, n (%) | 59 (5.0) | 18 (6.1) | 20 (6.8) | 8 (2.7) | 13 (4.4) | 0.102 |
| CPD, n (%) | 233 (19.7) | 48 (16.3) | 45 (15.3) | 72 (24.4) | 68 (23) | 0.007 |
| Rheumatoid disease, n (%) | 35 (3.0) | 8 (2.7) | 10 (3.4) | 5 (1.7) | 12 (4.1) | 0.373 |
| Peptic ulcer disease, n (%) | 18 (1.5) | 6 (2) | 2 (0.7) | 4 (1.4) | 6 (2) | 0.475 |
| Diabetes mellitus, n (%) | 396 (33.5) | 109 (36.9) | 100 (33.9) | 94 (31.9) | 93 (31.4) | 0.751 |
| Paraplegia, n (%) | 592 (50.1) | 141 (47.8) | 163 (55.3) | 159 (53.9) | 129 (43.6) | 0.015 |
| Malignancy, n (%) | 85 (7.2) | 19 (6.4) | 20 (6.8) | 21 (7.1) | 25 (8.4) | 0.796 |
| Severe liver disease, n (%) | 17 (1.4) | 7 (2.4) | 3 (1) | 4 (1.4) | 3 (1) | 0.437 |
| Renal disease, n (%) | 228 (19.3) | 61 (20.7) | 56 (19) | 55 (18.6) | 56 (18.9) | 0.922 |
| Metastatic solid tumor, n (%) | 39 (3.3) | 4 (1.4) | 9 (3.1) | 15 (5.1) | 11 (3.7) | 0.084 |
| Charlson comorbidity | 7.1 ± 2.8 | 7.2 ± 2.7 | 7.1 ± 2.7 | 7.2 ± 3.0 | 7.0 ± 2.8 | 0.787 |
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| Laboratory | ||||||
| Neutrophils, 109/L | 8.7 ± 4.4 | 5.4 ± 2.8 | 7.2 ± 2.9 | 9.7 ± 3.6 | 12.7 ± 4.3 | <0.001 |
| Lymphocytes, 109/L | 1.6 ± 0.9 | 2.3 ± 1.1 | 1.7 ± 0.7 | 1.3 ± 0.7 | 1.0 ± 0.5 | <0.001 |
| Platelets, 109/L | 226.0 ± 89.2 | 180.9 ± 77.7 | 215.4 ± 71.4 | 223.0 ± 83.2 | 284.5 ± 90.7 | <0.001 |
| WBC, 109/L | 10.0 (7.7, 13.6) | 7.7 (6.2, 10.1) | 8.9 (7.5, 11.1) | 11.1 (8.8, 13.8) | 13.8 (10.5, 17.6) | <0.001 |
| RBC, mean ± SD | 4.1 ± 0.8 | 4.0 ± 0.8 | 4.1 ± 0.8 | 4.2 ± 0.8 | 4.2 ± 0.8 | 0.008 |
| Hemoglobin, g/L | 12.3 ± 2.4 | 11.9 ± 2.4 | 12.3 ± 2.4 | 12.5 ± 2.3 | 12.3 ± 2.4 | 0.032 |
| RDW (%) | 14.3 ± 1.9 | 14.1 ± 1.9 | 14.3 ± 1.9 | 14.3 ± 1.8 | 14.6 ± 2.1 | 0.007 |
| Anion gap, mmol/L | 15.6 ± 4.3 | 14.6 ± 4.4 | 15.1 ± 3.7 | 16.1 ± 4.1 | 16.6 ± 4.7 | <0.001 |
| Bicarbonate, mmol/L | 22.9 ± 3.9 | 23.1 ± 3.7 | 23.3 ± 3.5 | 22.5 ± 3.9 | 22.6 ± 4.5 | 0.05 |
| Calcium, mg/dL | 8.7 ± 0.7 | 8.8 ± 0.8 | 8.8 ± 0.6 | 8.6 ± 0.8 | 8.6 ± 0.8 | <0.001 |
| Chloride, mmol/L | 103.1 ± 5.5 | 104.3 ± 5.2 | 102.9 ± 5.4 | 102.8 ± 5.2 | 102.5 ± 6.0 | <0.001 |
| Sodium, mmol/L | 138.9 ± 4.5 | 139.5 ± 4.1 | 139.0 ± 4.5 | 138.7 ± 4.1 | 138.6 ± 5.4 | 0.098 |
| Potassium, mmol/L | 4.3 ± 0.8 | 4.3 ± 0.7 | 4.3 ± 0.8 | 4.3 ± 1.0 | 4.3 ± 0.8 | 0.933 |
| Creatinine, mEq/L | 1.0 (0.8, 1.3) | 1.0 (0.8, 1.3) | 0.9 (0.8, 1.2) | 1.0 (0.8, 1.3) | 1.0 (0.8, 1.4) | 0.487 |
| BUN, mg/dL | 18.0 (14.0, 26.0) | 18.0 (14.0, 26.0) | 18.0 (12.0, 25.0) | 18.0 (14.0, 26.0) | 20.0 (14.5, 30.0) | 0.043 |
| Glucose, mg/dL | 126.0 (104.0, 166.0) | 114.0 (96.5, 143.0) | 117.0 (101.0, 154.0) | 127.0 (106.0, 165.5) | 148.0 (119.0, 193.2) | <0.001 |
| ALT, U/L | 20.0 (14.0, 31.0) | 18.0 (13.0, 26.8) | 19.0 (13.0, 28.0) | 21.0 (14.0, 33.0) | 22.0 (16.0, 39.0) | 0.001 |
| AST, U/L | 27.0 (19.0, 43.0) | 25.0 (19.0, 37.0) | 25.0 (19.0, 39.0) | 29.0 (19.0, 45.0) | 29.0 (20.0, 53.0) | 0.002 |
| INR | 1.1 (1.0, 1.3) | 1.1 (1.0, 1.3) | 1.1 (1.0, 1.3) | 1.2 (1.1, 1.3) | 1.1 (1.1, 1.3) | 0.02 |
| PT seconds | 12.5 (11.4, 14.4) | 12.4 (11.3, 14.5) | 12.2 (11.3, 13.9) | 12.8 (11.6, 14.6) | 12.7 (11.7, 14.4) | 0.002 |
| PTT seconds | 28.8 (25.7, 32.1) | 29.8 (26.2, 33.0) | 28.4 (25.7, 32.0) | 28.7 (25.3, 33.0) | 28.3 (25.7, 31.8) | 0.031 |
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| Drugs use and treatment, n (%) | ||||||
| Warfarin, n (%) | 271 (22.9) | 60 (20.3) | 67 (22.7) | 75 (25.4) | 69 (23.3) | 0.534 |
| NOAC, n (%) | 152 (12.9) | 44 (14.9) | 45 (15.3) | 39 (13.2) | 24 (8.1) | 0.035 |
| Antiplatelet agents, n (%) | 897 (76.0) | 221 (74.9) | 224 (75.9) | 236 (80) | 216 (73) | 0.235 |
| MV, n (%) | 441 (37.3) | 95 (32.2) | 87 (29.5) | 111 (37.6) | 148 (50) | <0.001 |
| PEGJ, n (%) | 88 (7.5) | 7 (2.4) | 18 (6.1) | 22 (7.5) | 41 (13.9) | <0.001 |
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| Scoring systems | ||||||
| APS III | 48.4 ± 24.4 | 43.1 ± 22.4 | 44.3 ± 22.0 | 47.3 ± 22.8 | 58.9 ± 27.0 | <0.001 |
| SAPS II | 34.8 ± 13.4 | 33.4 ± 13.0 | 33.3 ± 13.7 | 34.4 ± 12.7 | 38.0 ± 13.7 | <0.001 |
| OASIS | 33.8 ± 9.3 | 31.8 ± 8.9 | 32.7 ± 9.1 | 33.6 ± 8.8 | 37.2 ± 9.6 | <0.001 |
| LODS days | 4.0 (2.0, 7.0) | 4.0 (1.5, 6.0) | 4.0 (2.0, 6.0) | 4.0 (2.0, 7.0) | 5.0 (3.0, 8.0) | <0.001 |
| SOFA | 4.0 (2.0, 7.0) | 4.0 (2.0, 6.0) | 4.0 (2.0, 6.0) | 4.0 (2.0, 6.5) | 5.0 (3.0, 7.0) | <0.001 |
| GCS | 10.8 ± 3.8 | 11.5 ± 3.6 | 11.2 ± 3.6 | 10.8 ± 3.8 | 9.5 ± 4.0 | <0.001 |
| HASBLED | 1.4 (1.0, 1.8) | 1.0 (1.0, 2.0) | 1.0 (1.0, 2.0) | 1.0 (1.0, 2.0) | 1.0 (1.0, 2.0) | 0.332 |
| LOS.ICU | 3.7 (1.9, 7.4) | 3.1 (1.8, 6.1) | 3.2 (1.9, 6.8) | 3.8 (2.0, 8.3) | 4.4 (2.3, 9.1) | <0.001 |
| LOS.hospital | 8.7 (4.8, 15.8) | 7.3 (4.0, 13.2) | 8.3 (4.6, 14.8) | 9.0 (5.2, 17.4) | 11.2 (5.5, 18.8) | <0.001 |
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| Death, n (%) | ||||||
| ICU mortality, n (%) | 134 (11.3) | 21 (7.1) | 20 (6.8) | 40 (13.6) | 53 (17.9) | <0.001 |
| 30-day mortality, n (%) | 208 (17.6) | 31 (10.5) | 35 (11.9) | 53 (18) | 89 (30.1) | <0.001 |
| 90-day mortality, n (%) | 226 (19.1) | 34 (11.5) | 38 (12.9) | 61 (20.7) | 93 (31.4) | <0.001 |
Data were expressed as mean ± SD/median (interquartile ranges (IQR)) for continuous variables and percentage for categorical variables. SD, standard deviation; IQR, interquartile range; MAP, mean arterial pressure; SPO2, saturation of percutaneous oxygen; CHF, congestive heart failure; PVD, peripheral vascular disease; CPD, chronic pulmonary disease; WBC, white blood cell; RBC, red blood cell; RDW, red blood cell distribution width; BUN, blood urea nitrogen; ALT, alanine aminotransferase; AST, aspartate aminotransferase; INR, international normalized ratio; PT, prothrombin time; PTT, partial thromboplastin time; MV, mechanical ventilation; PEGJ, percutaneous gastrojejunostomy; NOAC, new oral anticoagulants; APS III, acute physiology score III; SAPS II, simplified acute physiology score; OASIS, Oxford acute severity of illness score; LODS, logistic organ dysfunction score; SOFA, sequential organ failure assessment; GCS, Glasgow coma scale; LOS.ICU, length of stay in the ICU; LOS.hospital, length of stay in the hospital.