Table 1.
Characteristics and laboratory findings of patients with negative and positive COVID-19 RT-PCR results in model development and validation cohort.
| Characteristics | Model Development Cohort |
Validation Cohort |
||||||
|---|---|---|---|---|---|---|---|---|
| COVID-19 negative (n = 681) | COVID-19 positive (n = 212) | P value | COVID-19 negative (n = 353) | COVID-19 positive (n = 84) | P value | |||
| Age, years Mean (SD) | 62.6 (24.7) | 40.6 (17.6) | <0.001* | 64.1 (22.7) | 42.3 (17.5) | <0.001* | ||
| Sex | 0.172 | 0.430 | ||||||
| Female | 361 (53.0%) | 101 (47.6%) | 168 (47.6%) | 44 (52.4%) | ||||
| Male | 320 (47.0%) | 111 (52.4%) | 185 (52.4%) | 40 (47.6%) | ||||
| Contact History | 30 (4.4%) | 82 (38.7%) | <0.001* | 15 (4.2%) | 36 (42.9%) | <0.001* | ||
| Signs and symptoms at presentation | ||||||||
| Asymptomatic | 25 (3.7%) | 19 (9.0%) | 0.002* | 20 (5.7%) | 10 (11.9%) | 0.042* | ||
| Fever | 310 (45.5%) | 107 (50.5%) | 0.207 | 156 (44.2%) | 43 (51.2%) | 0.247 | ||
| Cough | 304 (44.6%) | 119 (56.1%) | 0.003* | 151 (42.8%) | 50 (59.5%) | 0.006* | ||
| Shortness of breath | 216 (31.7%) | 22 (10.4%) | <0.001* | 116 (32.9%) | 11 (13.1%) | <0.001* | ||
| Chest Pain | 38 (5.6%) | 15 (7.1%) | 0.421 | 20 (5.7%) | 3 (3.6%) | 0.440 | ||
| Diarrhoea | 31 (4.6%) | 24 (11.3%) | <0.001* | 22 (6.2%) | 8 (9.5%) | 0.284 | ||
| Vomiting | 44 (6.5%) | 3 (1.4%) | 0.004* | 23 (6.5%) | 2 (2.4%) | 0.143 | ||
| Past Medical History | ||||||||
| Smoking | 81 (11.9%) | 8 (3.8%) | <0.001* | 34 (9.6%) | 1 (1.2%) | 0.010* | ||
| Diabetes | 162 (23.8%) | 8 (3.8%) | <0.001* | 84 (23.8%) | 8 (9.5%) | 0.004* | ||
| Hypertension | 269 (39.5%) | 21 (9.9%) | <0.001* | 155 (43.9%) | 16 (19.0%) | <0.001* | ||
| COPD | 28 (4.1%) | 0 (0.0%) | 0.003* | 16 (4.5%) | 0 (0.0%) | 0.047* | ||
| Chronic liver disease | 56 (8.2%) | 7 (3.3%) | 0.015* | 29 (8.2%) | 6 (7.1%) | 0.745 | ||
| Myocardial infarction | 46 (6.8%) | 3 (1.4%) | 0.003* | 37 (10.5%) | 0 (0.0%) | 0.002* | ||
| Active malignancy | 82 (12.0%) | 2 (0.9%) | <0.001* | 43 (12.2%) | 2 (2.4%) | 0.008* | ||
| Laboratory findings | ||||||||
| White cell count | 9.9 (5.3) | 5.5 (1.8) | <0.001* | 10.4 (5.8) | 5.9 (2.1) | <0.001* | ||
| (normal range: 4-10 × 109 cells/L) | ||||||||
| Leucocytosis | 266 (39.1%) | 4 (1.9%) | <0.001* | 147 (41.6%) | 4 (4.8%) | <0.001* | ||
| Neutrophil count | 7.4 (4.5) | 3.4 (1.5) | <0.001* | 7.9 (5.4) | 3.7 (1.9) | <0.001* | ||
| (normal range: 1.8-6.2 × 109 cells/L) | ||||||||
| Neutrophilia | 346 (50.8%) | 12 (5.7%) | <0.001* | 182 (51.6%) | 7 (8.3%) | <0.001* | ||
| Lymphocyte count | 1.4 (0.9) | 1.8 (3.4) | 0.017* | 1.6 (3.3) | 1.5 (0.6) | 0.874 | ||
| (normal range: 1.0-3.2 × 109 cells/L) | ||||||||
| ymphopenia | 268 (39.4%) | 52 (24.5%) | <0.001* | 150 (42.5%) | 20 (23.8%) | 0.002* | ||
| Neutrophil: Lymphocyte ratio | 8.9 (12.7) | 2.9 (2.6) | <0.001* | 11.3 (26.9) | 3.0 (2.4) | 0.005* | ||
| Platelet count (x109 cells/Litre)(normal range: 162– 341) |
250.0 (104.5) | 226.0 (65.7) | 0.002* | 247.9 (104.6) | 229.3 (75.2) | 0.125 | ||
| Albumin (normal range: 35·0–52·0) | 37.9 (7.3) | 41.8 (4.3) | <0.001* | 37.7 (7.6) | 41.6 (4.3) | <0.001* | ||
| Total Bilirubin (μmol/L) (normal range: 0·0–21·0) | 12.0 (14.9) | 7.4 (3.8) | <0.001* | 12.9 (15.2) | 8.5 (6.2) | 0.010* | ||
| Alanine Aminotransferase (U/L) (normal range 0·0–33·0) | 37.0 (126.3) | 27.4 (18.8) | 0.270 | 34.6 (67.6) | 30.1 (20.5) | 0.546 | ||
| eGFR (ml/min/1.73m2) | 75.1 (41.8) | 96.4 (26.5) | <0.001* | 73.5 (61.4) | 94.5 (24.7) | 0.002* | ||
| Radiological Findings | ||||||||
| CXR appearances, lung changes consistent with consolidation/GGO | 274 (40.2%) | 92 (43.4%) | 0.414 | 147 (41.6%) | 35 (41.7%) | 0.997 | ||
| CXR Pleural effusion absent | 582 (85.5%) | 212 (100.0%) | <0.001* | 295 (83.6%) | 83 (98.8%) | <0.001* | ||
| CXR Consolidation/GGO and Pleural effusion absent | 200 (29.4%) | 92 (43.4%) | <0.001* | 101 (28.6%) | 34 (40.5%) | 0.034* | ||
| Diagnosis for Presenting Illness | ||||||||
| URTI | 106 (15.6%) | NA | NA | 52 (14.7%) | NA | NA | ||
| Influenza | 10 (1.5%) | NA | NA | 10 (2.8%) | NA | NA | ||
| Non-Influenza Pneumonia | 170 (25.0%) | NA | NA | 75 (21.2%) | NA | NA | ||
All values are presented in mean (standard deviation), median (interquartile range), or in number (percentage), as appropriate.
COPD = Chronic obstructive pulmonary disease; eGFR = estimated glomerular filtration rate; CXR = Chest X-ray; GGO = ground glass opacity; RT-PCR = Reverse transcription polymerase chain reaction and URTI = Upper respiratory tract infection.
*
p-value < 0.05 for comparison between COVID-19 negative and positive using independent t-test and chi-squared test as appropriate.