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Georgetown University (n = 582) Virginia Commonwealth University (n = 223) University of Wisconsin (n = 102) Penn State University (n = 69) University of Florida (n = 133) University of California, LA (n = 333) Total (n = 1442) Disposition Discharge home 485 (83.3%) 190 (85.2%) 88 (86.3%) 68 (98.6%) 121 (91%) 301 (90.4%) 1253 (86.9%) Deceased 97 (16.7%) 33 (14.8%) 14 (13.7%) 1 (1.4%) 12 (9%) 32 (9.6%) 189 (13.1%) Demographics and vitals Age: median (interquartile range) 61 (22) 61 (22) 62 (25) 63 (29) 57 (39) 52 (30) 61 (25) Male: female 287:295 119:104 55:47 34:35 53:80 197:143 745:704 Clinical Predictors Discharged Alive Deceased P-value Categorical variable (n [%]) 1253 189 Female sex 615 (49.1) 84 (44.4) 0.267 Chronic obstructive pulmonary disease 180 (14.4) 44 (23.3) 0.002 Asthma 139 (11.1) 23 (12.2) 0.754 Diabetes 421 (33.6) 91 (48.1) <0.001 Cardiovascular disease 217 (17.3) 56 (29.6) <0.001 Temperature ≥ 39°C 69 (5.8) 11 (6.0) 1 Temperature ≥ 38°C 203 (17.0) 34 (18.6) 0.684 Age (years) <0.01 <50 396 (32.3) 9 (5) 50 to 65 415 (33.8) 42 (23.2) 66 to 79 270 (22) 79 (43.7) >80 146 (11.9) 51 (28.1) Body mass index >=40 kg/m2 147 (14.0) 27 (15.9) 0.604 Body mass index >=30 kg/m2 513 (49.0) 69 (40.6) 0.051 Oxygen saturation < 93% 82 (7.0) 36 (19.3) <0.001 Respiratory rate ≥ 25 breaths/minute 215 (17.9) 67 (35.6) <0.001 Respiratory rate ≥ 30 breaths/minute 96 (8.0) 40 (21.3) <0.001 C-reactive protein > 10 mg/dL 228 (33.0) 77 (67.5) <0.001 > 15 mg/dL 119 (17.2) 46 (40.4) <0.001 > 20 mg/dL 42 (6.1) 15 (13.2) 0.011 > 40 mg/dL 2 (0.3) 2 (1.8) 0.18 White blood cell count > 10 × 109/mL 172 (14.9) 60 (33.0) <0.001 Lymphocytes < 0.8 × 109/mL 271 (26.0) 68 (40.5) <0.001 Neutrophils > 8 × 109/mL 145 (13.9) 49 (29.2) <0.001 Serum creatinine >= 2.0 mg/dL 114 (9.9) 66 (36.1) <0.001 Continuous variables (median [interquartile range]) Age in years 59 [44.5, 71] 72.5 [64.8, 80] <0.001 Temperature °C 37.2 [36.8, 37.8] 37.2 [36.8, 37.8] 0.831 Oxygen saturation 97% [95%, 98%] 95% [93%, 97%] <0.001 Respiratory rate (breaths/minute) 20 [18, 23] 20 [18, 27] <0.001 White blood cell count (× 109/mL) 6.1 [4.6, 8.1] 7.5 [5.5, 11.8] <0.001 Lymphocytes (× 109/mL) 1.1 [0.8, 1.5] 0.8 [0.6, 1.3] <0.001 Neutrophils (× 109/mL) 4.4 [3, 6.2] 5.9 [4, 8.7] <0.001 Body mass index (kg/m2) 29.8 [25.3, 35.8] 28.5 [24.6, 35.8] 0.254 Serum creatinine (mg/dL) 0.9 [0.8, 1.3] 1.5 [1.1, 2.7] <0.001 C-reactive protein (mg//dL) 6.2 [2.4, 12.3] 13 [9, 17.3] <0.001 Lactate dehydrogenase (U/L) 313 [241, 409] 441 [349, 590] <0.001 - Table 3.
Multivariate Models Using Limited Clinical Data to Predict Mortality in Hospitalized Patients With COVID-19
Model using no laboratory values (COVID-NoLab) Predictors ß-Coefficient Std. Error Z Value Pr(>|z|) Constant −4.010 0.465 −8.620 0.001 Age 50 to 65 years 1.631 0.498 3.270 0.001 > 65 years 2.602 0.478 5.450 < 0.001 Respiratory rate ≥ 30/min 1.352 0.293 4.620 < 0.001 Oxygen saturation < 93% 1.036 0.288 3.600 < 0.001 AUROCC = 0.771 in the derivation group and 0.803 in the validation group. Model adding simple blood tests (COVID-SimpleLab) Predictors ß-Coefficient Std. Error Z Value Pr(>|z|) Constant −4.899 0.669 −7.330 0.000 C-reactive protein 11–20 mg/dL 1.316 0.329 4.010 0.000 > 20 mg/dL 1.057 0.510 2.080 0.038 Respiratory rate ≥ 30/min 1.522 0.403 3.770 0.000 Oxygen saturation < 93% 0.911 0.418 2.180 0.029 Age 50 to 65 years 1.310 0.661 1.980 0.047 > 65 years 2.233 0.640 3.490 0.000 Asthma 0.953 0.428 2.230 0.026 White blood cell count > 10 × 109/mL 0.579 0.348 1.660 0.097 Serum creatinine > 2.0 mg/dL 1.152 0.348 3.310 0.001 AUROCC = 0.835 in the derivation group and 0.833 in the validation group. AUROCC, area under the receiver operating characteristic curve.
- Table 4.
Calculation of the COVID-NoLab and COVID-SimpleLab Risk Scores and Their Classification Accuracy in Derivation and Validation Groups
Derivation Group Validation Group COVID-NoLab Score Mortality Mortality Clinical Predictor Points Risk Group n/Total (%) SSLR n/Total (%) SSLR Age Low (0 to 1) 3/167 (1.8%) 0.10 1/129 (0.8%) 0.06 50 to 65 years 3 Moderate (2 to 5) 74/543 (13.6%) 0.89 40/350 (11.4%) 0.95 > 65 years 5 High (6+) 44/96 (45.8%) 4.79 23/57 (40.4%) 4.99 Respiratory rate ≥ 30 3 O2 saturation < 93% 2 Derivation Group Validation Group COVID-SimpleLab Score Mortality Mortality Clinical Predictor Points Risk Group n/Total (%) SSLR n/Total (%) SSLR C-reactive protein > 10 mg/dL 5 Low (0 to 7) 0/129 (0.0%) 0.0 1/97 (1.0%) 0.07 Respiratory rate ≥ 30 5 Moderate (8 to 11) 10/131 (8.3%) 0.46 9/99 (9.1%) 0.66 O2 saturation < 93% 4 High (12+) 58/185 (45.7%) 2.53 29/99 (29.3%) 2.73 Age 50 to 65 years 6 > 65 years 8 Asthma 4 White blood cell count > 10 × 109/mL 3 Serum creatinine > 2.0 mg/dL 4 SSLR, stratum specific likelihood ratio.
Study Performance in Original Study Performance in 5 US Sites Lu et al., 20209 Low risk: 0% Low risk: 2/108 (1.8%) Moderate risk: 6% Moderate risk: 24/359 (6.7%) High risk: 33% High risk: 87/324 (26.9%) Xie et al., 202010 AUROCC (derivation) = 0.893 AUROCC = 0.7981 AUROCC (test) = 0.980 Hosmer–Lemeshow P = .23 Yan et al., 202011 Low risk: 3/189 (1.6%) Low risk: 10/243 (4.1%) High risk: 157/162 (96.9%) High risk: 85/374 (22.7%) AUROCC, area under the receiver operating characteristic curve.
See appendix for details regarding calculation of risk scores.
Clinical Variable Normal Range Units Demographics Health system Hospital Age in years years Sex Race Comorbidities COPD Asthma Cardiovascular disease Hypertension Diabetes mellitus Vitals Respiratory rate 12 to 20 breaths/minute Temperature 36.5 to 37.5 degrees Celsius Heart rate 60 to 100 beats/minute Systolic blood pressure 90 to 139 mm Hg Diastolic blood pressure 50 to 89 mm Hg BMI 20 to 24.9 kg/m2 O2 saturation room air 95% to 100% % Laboratory tests White blood cell count 4.5 to 10 1000 cells/microliter Lymphocyte count 1000 to 4800 cells/microliter Neutrophil count 2500 to 7500 cells/microliter Platelets 150,000 to 450,000 platelets/microliter Serum creatinine 0.5 to 1.2 mg/dL Blood urea nitrogen 7 to 20 mg/dL Lactate dehydrogenase (LDH) 140 to 280 units/L Aspartate aminotransferase (AST) 10 to 40 units/L Alanine aminotransferase (ALT) 7 to 56 units/L Ferritin 12 to 300 ng/mL Troponin T or I 0 to 0.4 ng/mL C-reactive protein (CRP) < 10 mg/dL D-dimer < 0.5 mg/L Interleukin-6 (IL6) 0 to 16 pg/mL Outcome variables Vasopressor needed in first 24 hours Discharge disposition (discharged home, still hospitalized, deceased) ICU admit during hospitalization (Y/N) Mechanical ventilation (Y/N) Number of days hospitalized (including observation status) Number of days in the ICU Number of days on ventilator COPD, Chronic obstructive pulmonary disease; BMI, body mass index.
Coef. Std. Err. z P > z Points White blood cell count (WBC) > 10 0.586 0.279 2.100 0.036 1 Resp rate ≥ 30 1.404 0.344 4.080 0.000 2 O2 sat < 93% 0.986 0.337 2.930 0.003 2 Age 50 to 65 3.101 1.031 3.010 0.003 5 > 65 4.179 1.020 4.100 0.000 7 _cons −5.699 1.018 −5.600 0.000 Proposed point score and its accuracy for prediction of mortality in development and validation data sets
Development Risk Group (Points) Deaths Survivors Total Mortality LR Low: 0 to 2 0 163 163 0.0% 0.00 Mod: 3 to 6 20 192 212 10.4% 0.65 High: 7+ 77 254 331 30.3% 1.90 97 609 706 Validation Risk Group (Points) Deaths Survivors Total Mortality LR Low: 0 to 2 5 108 113 4.4% 0.27 Mod: 3 to 6 6 113 119 5.0% 0.31 High: 7+ 58 180 238 24.4% 1.87 69 401 470 Model using clinical predictors + c-reactive protein (CRP) only
Coef. Std. Err. z P > z Points CRP > 10 to 20 mg/dL 1.522 0.309 4.920 0.000 3 > 20 mg/dL 0.974 0.539 1.810 0.071 2 Respiratory rate ≥ 30 1.246 0.420 2.970 0.003 3 Age 50 to 65 1.798 0.786 2.290 0.022 4 > 65 3.279 0.765 4.290 0.000 7 Asthma 0.977 0.417 2.340 0.019 2 _cons −5.236 0.782 −6.690 0.000 Training Risk Group Deaths Survivors Total Prev LR 0 to 4 3 176 179 1.7% 0.10 5 to 8 21 157 178 11.8% 0.76 9+ 47 71 118 39.8% 3.77 71 404 475 Testing Risk Group Deaths Survivors Total Prev LR 0 to 4 5 108 113 4.4% 0.30 5 to 8 11 115 126 8.7% 0.62 9+ 26 51 77 33.8% 3.33 42 274 316
In this issue
Jump to section
- Article
- Abstract
- Introduction
- Methods and Materials
- Results
- Discussion
- Conclusion
- Appendix 1. Full List of Requested Clinical Variables; Predictor Variables only Included if Ordered Within 24 Hours of Admission
- Appendix 2. This Summarizes the Receiver Operating Characteristic (ROC) Curves and Calibration Plots for Each Model.
- Appendix 3. Additional Model Using Clinical Variables and Complete Blood Count Only.
- Notes
- References
- Figures & Data
- References
- Info & Metrics
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