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Table 1 Comparison between the training set and the validation set

From: Prediction of patients requiring intensive care for COVID-19: development and validation of an integer-based score using data from Centers for Disease Control and Prevention of South Korea

  Total (n = 4663) Training set (n = 3238) Validation set (n = 1425) P value
Demographic
 Age 55.0 [37.0;67.0] 56.0 [41.0;68.0] 53.0 [30.0;66.0] < 0.001
 Sex, male 1841 (39.5%) 1182 (36.5%) 659 (46.2%) < 0.001
Symptoms and signs
 Initial body temperature 36.8 [36.5;37.3] 36.9 [36.5;37.3] 36.8 [36.5;37.2] 0.001
 Cough 1944 (41.7%) 1523 (47.0%) 421 (29.5%) < 0.001
 Sputum 1344 (28.8%) 1049 (32.4%) 295 (20.7%) < 0.001
 Hemoptysis 26 (0.6%) 23 (0.7%) 3 (0.2%) 0.058
 Sore throat 682 (14.6%) 514 (15.9%) 168 (11.8%) < 0.001
 Rhinorrhea 440 (9.4%) 334 (10.3%) 106 (7.4%) 0.002
 Chest pain 351 (7.5%) 294 (9.1%) 57 (4.0%) < 0.001
 Myalgia 733 (15.7%) 583 (18.0%) 150 (10.5%) < 0.001
 Arthralgia 18 (0.4%) 16 (0.5%) 2 (0.1%) 0.124
 Lethargic 179 (3.8%) 143 (4.4%) 36 (2.5%) 0.003
 Dyspnea 632 (13.6%) 528 (16.3%) 104 (7.3%) < 0.001
 Headache 773 (16.6%) 612 (18.9%) 161 (11.3%) < 0.001
 Nausea, vomiting 216 (4.6%) 171 (5.3%) 45 (3.2%) 0.002
 Diarrhea 400 (8.6%) 333 (10.3%) 67 (4.7%) < 0.001
Medical history
 Pregnancy 17 (0.4%) 12 (0.4%) 5 (0.4%) 1.000
 Diabetes 704 (15.1%) 510 (15.8%) 194 (13.6%) 0.067
 Heart failure 66 (1.4%) 40 (1.2%) 26 (1.8%) 0.151
 Hypertension 1183 (25.4%) 847 (26.2%) 336 (23.6%) 0.068
 Chronic cardiac disease 188 (4.0%) 138 (4.3%) 50 (3.5%) 0.261
 Asthma 118 (2.5%) 93 (2.9%) 25 (1.8%) 0.033
 COPD 40 (0.9%) 34 (1.1%) 6 (0.4%) 0.048
 Chronic kidney disease 56 (1.2%) 45 (1.4%) 11 (0.8%) 0.101
 Cancer 154 (3.3%) 111 (3.4%) 43 (3.0%) 0.526
 Chronic liver disease 72 (1.5%) 51 (1.6%) 21 (1.5%) 0.897
 Chronic neurologic disorder 41 (0.9%) 23 (0.7%) 18 (1.3%) 0.091
 Chronic hematologic disorder 34 (0.7%) 27 (0.8%) 7 (0.5%) 0.280
 HIV infection 9 (0.2%) 7 (0.2%) 2 (0.1%) 0.856
 Autoimmune disease 32 (0.7%) 25 (0.8%) 7 (0.5%) 0.380
 Dementia 320 (6.9%) 172 (5.3%) 148 (10.4%) < 0.001
 Smoking     < 0.001
  Never smoker 4280 (91.8%) 3034 (93.7%) 1246 (87.4%)  
  Ex-smoker 131 (2.8%) 94 (2.9%) 37 (2.6%)  
  Current smoker 252 (5.4%) 110 (3.4%) 142 (10.0%)  
 ADL     < 0.001
  Normal 4011 (86.0%) 2884 (89.1%) 1127 (79.1%)  
  Partially dependent 358 (7.7%) 194 (6.0%) 164 (11.5%)  
  Totally dependent 294 (6.3%) 160 (4.9%) 134 (9.4%)  
Imaging and laboratory findings
 Chest X-ray infiltration 1650 (35.4%) 1229 (38.0%) 421 (29.5%) < 0.001
 Hemoglobin level, g/dL 13.2 [12.1;14.4] 13.2 [12.2;14.3] 13.3 [12.1;14.5] 0.066
 Platelet count, 103/μL 224.0 [176.0;280.0] 227.0 [178.0;283.0] 218.0 [175.0;273.0] 0.002
 WBC count, 103/μL 5.7 [4.4;7.1] 5.7 [4.5; 7.2] 5.7 [4.4; 7.0] 0.301
 Lymphocyte, % 28.7 [20.9;36.2] 28.7 [20.9;36.1] 28.6 [21.3;36.5] 0.638
 Hematocrit, % 39.1 [36.2;42.3] 39.0 [36.1;42.1] 39.5 [36.2;42.8] 0.018
 AST level, IU/L 24.0 [19.0;33.0] 25.0 [20.0;34.0] 23.0 [19.0;32.0] < 0.001
 ALT level, IU/L 20.0 [14.0;31.0] 20.0 [14.0;31.0] 19.0 [13.0;30.0] < 0.001
 Albumin level, g/dL 4.2 [3.8;4.5] 4.1 [3.8; 4.4] 4.3 [3.9; 4.6] < 0.001
 BUN level, mg/dL 12.3 [10.0;15.8] 12.5 [10.0;16.0] 12.0 [9.7;15.0] < 0.001
 Creatinine level, mg/dL 0.7 [0.6;0.9] 0.7 [0.6; 0.9] 0.8 [0.6; 0.9] 0.342
Outcomes
 Requiring ICU 444 (9.5%) 320 (9.9%) 124 (8.7%) 0.226
 Admission to ICU 213 (4.6%) 113 (3.5%) 70 (5.0%) 0.016
 Mechanical ventilation 49 (1.1%) 35 (1.1%) 14 (1.0%) 0.697
 ECLS 28 (0.6%) 22 (0.7%) 6 (0.4%) 0.397
 Vasopressor treatment 118 (2.5%) 83 (2.6%) 35 (2.5%) 0.182
 Death 217 (4.7%) 141 (4.3%) 76 (5.4%) 0.113
  1. Values are number (%) or median [interquartile range]
  2. ADL activities of daily living, AST aspartate aminotransferase, ALT alanine aminotransferase, BUN blood urea nitrogen, COPD chronic obstructive pulmonary disease, ECLS extracorporeal life support, HIV human immunodeficiency virus, ICU intensive care unit, WBC white blood cell