Table 2.
Patient characteristics and demographics grouped by test or train status.
| Characteristic | N | Overall, N = 781 | Test, N = 481 | Training, N = 301 | p-value2 |
|---|---|---|---|---|---|
| Symptom duration days | 78 | 7 (5, 10) | 8 (6, 10) | 6 (2, 10) | 0.076 |
| Length of stay (hours) | 75 | 198 (100, 332) | 206 (104, 331) | 186 (80, 376) | 0.98 |
| Age (years) | 78 | 61 (46, 74) | 56 (41, 72) | 66 (58, 76) | 0.028 |
| Sex | 78 | 0.62 | |||
| F | 26 (33%) | 15 (31%) | 11 (37%) | ||
| M | 52 (67%) | 33 (69%) | 19 (63%) | ||
| Smoking status | 78 | 0.90 | |||
| Ex-smoker | 31 (40%) | 19 (40%) | 12 (40%) | ||
| Never | 36 (46%) | 21 (44%) | 15 (50%) | ||
| Unknown | 7 (9.0%) | 5 (10%) | 2 (6.7%) | ||
| Yes | 4 (5.1%) | 3 (6.2%) | 1 (3.3%) | ||
| Ethnicity | 78 | 0.034 | |||
| White - British | 47 (60%) | 27 (56%) | 20 (67%) | ||
| White – Any other white background | 6 (7.7%) | 5 (10%) | 1 (3.3%) | ||
| Asian or Asian British - Indian | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Asian or Asian British – Any other Asian background | 13 (17%) | 11 (23%) | 2 (6.7%) | ||
| Black or Black British - Caribbean | 2 (2.6%) | 2 (4.2%) | 0 (0%) | ||
| Black or Black British - African | 6 (7.7%) | 1 (2.1%) | 5 (17%) | ||
| Unknown | 1 (1.3%) | 1 (2.1%) | 0 (0%) | ||
| Clinical Metrics | |||||
| Hypertension | 78 | 0.008 | |||
| No | 45 (58%) | 34 (71%) | 11 (37%) | ||
| Unknown | 4 (5.1%) | 2 (4.2%) | 2 (6.7%) | ||
| Yes | 29 (37%) | 12 (25%) | 17 (57%) | ||
| CV disease | 78 | 0.55 | |||
| No | 59 (76%) | 38 (79%) | 21 (70%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 16 (21%) | 9 (19%) | 7 (23%) | ||
| Resp Disease other | 78 | 0.39 | |||
| No | 54 (69%) | 32 (67%) | 22 (73%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 21 (27%) | 15 (31%) | 6 (20%) | ||
| Asthma | 78 | 0.71 | |||
| No | 62 (79%) | 39 (81%) | 23 (77%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 13 (17%) | 8 (17%) | 5 (17%) | ||
| COPD | 78 | 0.22 | |||
| No | 68 (87%) | 41 (85%) | 27 (90%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 7 (9.0%) | 6 (12%) | 1 (3.3%) | ||
| CKD | 78 | 0.018 | |||
| No | 69 (88%) | 46 (96%) | 23 (77%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 6 (7.7%) | 1 (2.1%) | 5 (17%) | ||
| CLD | 78 | 0.80 | |||
| No | 72 (92%) | 45 (94%) | 27 (90%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 3 (3.8%) | 2 (4.2%) | 1 (3.3%) | ||
| Diabetes | 78 | 0.048 | |||
| No | 56 (72%) | 39 (81%) | 17 (57%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 19 (24%) | 8 (17%) | 11 (37%) | ||
| Active malignancy | 78 | 0.48 | |||
| No | 69 (88%) | 44 (92%) | 25 (83%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 6 (7.7%) | 3 (6.2%) | 3 (10%) | ||
| Dementia | 78 | 0.45 | |||
| No | 67 (86%) | 43 (90%) | 24 (80%) | ||
| Unknown | 3 (3.8%) | 1 (2.1%) | 2 (6.7%) | ||
| Yes | 8 (10%) | 4 (8.3%) | 4 (13%) | ||
| Immunosuppressed + | 78 | 0.004 | |||
| No | 70 (90%) | 47 (98%) | 23 (77%) | ||
| Unknown | 4 (5.1%) | 1 (2.1%) | 3 (10%) | ||
| Yes | 4 (5.1%) | 0 (0%) | 4 (13%) | ||
| Abx during admission | 78 | 72 (92%) | 44 (92%) | 28 (93%) | >0.99 |
| Blood Chemistry | |||||
| Haemoglobin | 77 | 132 (124, 148) | 132 (124, 152) | 132 (127, 144) | 0.39 |
| White blood cells | 77 | 7.8 (5.7, 11.5) | 7.1 (5.6, 11.2) | 9.0 (6.0, 11.7) | 0.32 |
| Platelets | 77 | 236 (184, 291) | 228 (181, 289) | 260 (191, 291) | 0.45 |
| Neutrophils | 77 | 6.0 (4.0, 9.6) | 4.9 (3.8, 8.5) | 7.4 (4.4, 9.7) | 0.14 |
| Lymphocytes | 77 | 1.00 (0.80, 1.20) | 1.00 (0.80, 1.20) | 1.00 (0.70, 1.20) | 0.56 |
| Sodium | 77 | 135 (133, 138) | 136 (134, 138) | 134 (133, 136) | 0.011 |
| Potassium | 71 | 4.00 (3.65, 4.40) | 3.95 (3.75, 4.40) | 4.00 (3.65, 4.35) | 0.94 |
| Urea | 77 | 6.3 (4.7, 9.9) | 5.8 (4.3, 9.5) | 7.2 (5.8, 9.9) | 0.20 |
| Creatine | 77 | 86 (67, 110) | 84 (66, 102) | 87 (76, 125) | 0.47 |
| Albumin | 73 | 34 (30, 35) | 34 (31, 36) | 31 (28, 34) | 0.012 |
| Bilirubin | 73 | 11 (8, 13) | 11 (8, 14) | 10 (8, 13) | 0.71 |
| Alanine Aminotransferase | 70 | 34 (24, 70) | 34 (26, 65) | 36 (22, 75) | 0.57 |
| Alkaline Phosphatase | 73 | 89 (61, 115) | 93 (61, 117) | 84 (62, 106) | 0.54 |
| Total Protein | 72 | 70 (66, 73) | 70 (67, 75) | 69 (66, 72) | 0.41 |
| LDH | 52 | 766 (561, 1,133) | 698 (540, 932) | 1,022 (661, 1,380) | 0.061 |
| Ferritin | 61 | 678 (354, 1,693) | 638 (421, 1,291) | 970 (339, 1,978) | 0.51 |
| D-dimer | 45 | 469 (320, 942) | 448 (350, 886) | 535 (300, 884) | 0.89 |
| Trop | 60 | 12 (5, 46) | 10 (5, 50) | 13 (9, 34) | 0.33 |
| CRP | 77 | 120 (52, 164) | 92 (44, 155) | 135 (108, 185) | 0.046 |
| Cytokines/Chemokines | |||||
| IL-6 (pg/ml) | 78 | 52 (32, 106) | 41 (25, 85) | 82 (44, 174) | 0.002 |
| TNFα (pg/ml) | 78 | 20 (17, 25) | 20 (15, 24) | 21 (18, 28) | 0.090 |
| IL-8(pg/ml) | 78 | 35 (26, 59) | 34 (21, 52) | 49 (32, 72) | 0.006 |
| IL-1β9 (pg/ml) | 78 | 0.39 (0.26, 0.56) | 0.36 (0.24, 0.49) | 0.46 (0.29, 0.61) | 0.20 |
| GM-CSF (pg/ml) | 78 | 1.30 (0.80, 1.86) | 1.21 (0.76, 1.65) | 1.47 (0.82, 2.58) | 0.20 |
| IFNg (pg/ml) | 78 | 12 (4, 27) | 13 (2, 27) | 11 (6, 28) | 0.73 |
| IL-10 (pg/ml) | 78 | 16 (10, 28) | 14 (8, 24) | 20 (14, 31) | 0.052 |
| IL-33(pg/ml) | 78 | 0.35 (0.17, 0.61) | 0.34 (0.17, 0.51) | 0.36 (0.17, 0.69) | 0.50 |
| Physiological Metrics | |||||
| Heart Rate | 78 | 98 (85, 109) | 102 (88, 110) | 90 (85, 100) | 0.034 |
| Systolic Blood Pressure | 78 | 132 (122, 143) | 130 (120, 138) | 134 (126, 145) | 0.20 |
| Respiration Rate | 78 | 26 (20, 32) | 24 (20, 32) | 26 (22, 33) | 0.17 |
| Oxygen Saturation | 78 | 95 (92, 96) | 96 (93, 97) | 94 (91, 96) | 0.051 |
| Temperature (°C) | 76 | 37.20 (36.60, 38.20) | 37.20 (36.60, 38.23) | 37.20 (36.68, 38.12) | 0.88 |
| O2 | 78 | 37 (47%) | 18 (38%) | 19 (63%) | 0.026 |
| NEWS2 | 76 | 6 (4, 7) | 6 (3, 7) | 6 (5, 6) | 0.62 |
| CXR | 78 | 77 (99%) | 48 (100%) | 29 (97%) | 0.38 |
| Consolidation or infiltrates | 77 | 66 (86%) | 40 (83%) | 26 (90%) | 0.52 |
| CT | 78 | 8 (10%) | 6 (12%) | 2 (6.7%) | 0.70 |
| ICU Specific Metrics | |||||
| Duration O2* | 78 | 19 (5, 112) | 16 (4, 88) | 24 (14, 179) | 0.091 |
| ICU admission | 78 | 27 (35%) | 15 (31%) | 12 (40%) | 0.43 |
| NIV duration* | 78 | 0 (0, 13) | 0 (0, 16) | 0 (0, 9) | 0.93 |
| IV duration* | 78 | 0 (0, 0) | 0 (0, 0) | 0 (0, 151) | 0.030 |
| Optiflow duration* | 78 | 7 (9.0%) | 3 (6.2%) | 4 (13%) | 0.42 |
| ECMO* | 75 | 1 (1.3%) | 1 (2.1%) | 0 (0%) | >0.99 |
| Died within 30 days of admission* | 77 | 15 (19%) | 6 (12%) | 9 (31%) | 0.047 |
1Median (IQR); n (%) 2Wilcoxon rank sum test; Pearson’s Chi-squared test; Fisher’s exact test.
* Metric excluded from machine learning analysis.
+Immunosuppressed definition derived from UKHSA Influenza treatment guidance.
ICU, Intensive Care Unit; CV, Cardiovascular; COPD, Chronic obstructive pulmonary disease; CKD, Chronic kidney disease; CLD, Chronic liver disease; LDH, Lactate dehydrogenase; IL, Interleukin; TNF, Tumour necrosis factor; GMCSF, Granulocyte-macrophage colony-stimulating factor; IFN, Interferon; NEWS2, National early warning score 2; O2, administration of supplementary oxygen; CXR, Chest x-ray; CT, Computational tomography; NIV, Non-invasive ventilation; IV, Invasive ventilation; ECMO, Extracorporeal membrane oxygenation.