Table 1
Baseline Characteristics of Hospitalised CoVID-19 Patients
| Overall (N=158) | |
|---|---|
| Clinical Characteristics | |
| Age | 56.2 (16.8) |
| BMI | 31.3 (8.0) |
| Male | 81 (51.3%) |
| Active Tobacco Use | 9 (5.8%) |
| White, non-Hispanic | 30 (19.5%) |
| Black | 53 (34.4%) |
| Hispanic | 45 (29.2%) |
| Asian | 11 (7.1%) |
| Other | 15 (9.7%) |
| Diabetes | 47 (30.3%) |
| Hypertension | 87 (56.1%) |
| COPD | 11 (7.1%) |
| Creatinine >2 mg/dL on Admission | 4 (2.5%) |
| Cirrhosis | 3 (1.9%) |
| Coronary Artery Disease | 18 (11.6%) |
| Active Cancer | 11 (7.1%) |
| Immunosuppressed | 10 (6.5%) |
| Presenting Symptoms | |
| Subjective Fever | 111 (74.0%) |
| Cough | 126 (82.4) |
| Diarrhoea | 40 (26.8%) |
| Nausea/Vomiting | 42 (28.2%) |
| Myalgia | 34 (22.8%) |
| Dyspnoea | 116 (75.3%) |
| Duration of Symptoms | 6.7 (4.6) |
| Chest X-Ray Findings* | |
| Unilateral Infiltrate | 28 (17.8%) |
| Bilateral Infiltrate | 102 (65%) |
| Other Findings | 28 (17.8%) |
| Clinical Course | |
| Intubation Indicated | 64 (40.5%) |
| Vasopressors Indicated | 42 (26.6%) |
| Prone Positioned | 24 (15.2%) |
| Deceased | 4 (2.5%) |
| Discharge | 55 (36.9%) |
Table 2
Characteristics of Intubated CoVID-19 Patients
| Overall (N=64) | |
|---|---|
| Clinical Characteristics | |
| Oxygen Requirement on Admission in Litres of Oxygen | 5.6 (13.2) |
| Highest Oxygen Requirement Stable >1 Hour within 24 Hours of Admission in Litres of Oxygen | 5.0 (4.1) |
| Use of Non-Invasive Ventilation Before Intubation | 1 (1.6%) |
| Oxygen Requirement within one hour of Intubation in Litres of Oxygen | 12.9 (12.7) |
| SOFA on Intubation | 4.5 (2.1) |
| Days Intubated | 11.926 (8.519) |
| Pa02 to Fi02 at 8 Hour Intervals | |
| P:F Ratio at 8h | 146.3 (84.1) |
| P:F Ratio at 16h | 194.9 (69.1) |
| P:F Ratio at 24h | 204.0 (63.4) |
| P:F Ratio at 32h | 216.8 (65.5) |
| P:F Ratio at 40h | 216.2 (65.9) |
| P:F Ratio at 48h | 204.7 (75.3) |
| P:F Ratio at 56h | 212.5 (73.9) |
| P:F Ratio at 64h | 217.0 (71.2) |
| P:F Ratio at 72h | 219.9 (81.4) |
| Pa02 to (Fi02*PEEP) at 8 Hour Intervals | |
| P:FP Ratio at 8h | 12.3 (7.4) |
| P:FP Ratio at 16h | 17.3 (9.8) |
| P:FP Ratio at 24h | 17.5 (8.0) |
| P:FP Ratio at 32h | 19.1 (8.8) |
| P:FP Ratio at 40h | 20.1 (10.8) |
| P:FP Ratio at 48h | 18.2 (13.7) |
| P:FP Ratio at 56h | 19.1 (9.5) |
| P:FP Ratio at 64h | 20.6 (12.8) |
| P:FP Ratio at 72h | 21.2 (13.0) |
Table 3
Characteristics of Hospitalised CoVID-19 Patients Stratified by Intubation Status
| Not Intubated (N=94) | Intubated (N=64) | N-Missing (Not intubated/ Intubated) | p-value | |
|---|---|---|---|---|
| Clinical Characteristics | ||||
| Age | 55.36 (17.33) | 57.32 (15.90) | 0/1 | 0.415 |
| BMI | 30.85 (7.84) | 32.01 (8.2) | 5/0 | 0.436 |
| Male | 45 (47.9%) | 36 (56.2%) | NA | 0.333 |
| Active Tobacco Use | 4 (4.3%) | 5 (8.1%) | NA | 0.485 |
| Non-White Race and/or Hispanic | 71 (76.3%) | 53 (86.9%) | NA | 0.145 |
| Ethnicity | ||||
| Diabetes | 21 (22.3%) | 26 (42.6%) | NA | 0.012 |
| Hypertension | 52 (55.3%) | 35 (57.4%) | NA | 0.869 |
| COPD | 6 (6.4%) | 5 (8.2%) | NA | 0.753 |
| Creatinine >2 mg/dL on Admission | 1 (1.1%) | 3 (4.8%) | NA | 0.303 |
| Cirrhosis | 1 (1.1%) | 2 (3.3%) | NA | 0.562 |
| Coronary Artery Disease | 12 (12.8%) | 6 (9.8%) | NA | 0.620 |
| Active Cancer | 6 (6.4%) | 5 (8.2%) | NA | 0.753 |
| Immunosuppressed | 8 (8.6%) | 2 (3.3%) | NA | 0.317 |
| Presenting Symptoms | ||||
| Subjective Fever | 72 (77.4%) | 39 (68.4%) | NA | 0.253 |
| Cough | 75 (79.8%) | 51 (86.4%) | NA | 0.385 |
| Diarrhoea | 30 (32.3%) | 10 (17.9%) | NA | 0.059 |
| Nausea/Vomiting | 33 (35.5%) | 9 (16.1%) | NA | 0.014 |
| Myalgia | 20 (21.5%) | 14 (25%) | NA | 0.688 |
| Dyspnoea | 74 (78.7%) | 42 (70%) | NA | 0.253 |
| Duration of Symptoms | 6.7 (4.53) | 6.57 (4.81) | 1/6 | 0.796 |
| Chest X-Ray Findings* | ||||
| Clear | 12 (13.8%) | 4 (6.3%) | NA | 0.192 |
| Unilateral Infiltrate | 21 (22.3%) | 7 (11.1%) | NA | 0.090 |
| Bilateral Infiltrate | 51 (54.3%) | 51 (81%) | NA | <0.001 |
| Pleural Effusion | 0 (0%) | 2 (3.2%) | NA | 0.159 |
| Other Finding | 6 (6.4%) | 3 (4.8%) | NA | 0.741 |
| Laboratory Findings* | ||||
| CRP mg/L | 70.34 (60.5) | 142.50 (83.36) | 2/6 | <0.001 |
| LDH U/L | 311.53 (102.3) | 415.37 (160.22) | 5/13 | <0.001 |
| D-dimer FEU | 1199.23 (1692.86) | 4475.20 (14140.16) | 15/14 | 0.033 |
| Ferritin ng/mL | 428.47 (426.81) | 790.62 (1236.12) | 7/17 | 0.079 |
| Neutrophils x10^9/L | 4.55 (2.11) | 7.20 (3.68) | 59/24 | <0.001 |
| Lymphocytes x10^9/L | 3.60 (14.03) | 1.08 (0.63) | 59/24 | 0.067 |
| NLR | 4.20 (2.41) | 8.33 (6.51) | 59/24 | <0.001 |
| Clinical Course | ||||
| Deceased | 2 (2.1%) | 2 (3.1%) | NA | 1.00 |
| Discharged | 53 (57.6%) | 2 (3.5%) | NA | <0.001 |
[i] Data are reported as number (%) or mean (standard deviation). * Data collected within 24 hours of hospital admission. BMI = body mass index, COPD = chronic obstructive pulmonary disease, CRP = C-reactive protein, LDH = lactate dehydrogenase, FEU = fibrinogen equivalent units, NLR = neutrophil-lymphocyte ratio. NA signifies no missing data.
Table 4
Covariate Effects on Odds of Intubation
| Unadjusted | Adjusted * | |||||
|---|---|---|---|---|---|---|
| Term | OR | 95% CI | p-value | OR | 95% CI | p-value |
| 1 SD change in CRP (78.0 mg/L) | 3.05 | (1.9, 4.8) | <0.001 | 2.81 | (1.8, 4.5) | <0.001 |
| 1 SD change in LDH (135.6 U/L) | 2.31 | (1.5, 3.6) | <0.001 | 2.10 | (1.3, 3.3) | 0.002 |
| 1 SD change in Log D-Dimer (0.94 log FEU) | 1.47 | (1, 2.2) | 0.048 | 1.33 | (0.8, 2.1) | 0.22 |
| 1 SD change in NLR (5.4) | 1.94 | (1.1, 3.5) | 0.031 | 2.21 | (1.1, 4.5) | 0.033 |
| 1 SD change in Log Ferritin (1.12 log ng/mL) | 1.45 | (1, 2.1) | 0.055 | 1.29 | (0.9, 1.9) | 0.23 |
| 1 SD change in BMI (8.0 kg/m2) | 1.15 | (0.8, 1.6) | 0.39 | 1.07 | (0.7, 1.6) | 0.71 |
| 1 SD change in age (16.8 years) | 1.13 | (0.8, 1.6) | 0.45 | 1.15 | (0.8, 1.7) | 0.48 |
| Symptom Duration | 0.99 | (0.9, 1.1) | 0.86 | 0.99 | (0.9, 1.1) | 0.72 |
| DM | 2.52 | (1.3, 5.1) | 0.010 | 1.98 | (0.9, 4.3) | 0.081 |
| Ethnicity/Race is Non-White | 2.08 | (0.9, 5) | 0.10 | 1.96 | (0.8, 5.1) | 0.17 |
| Bilateral Infiltrate on X-Ray | 3.6 | (1.7, 7.6) | 0.001 | 3.39 | (1.5, 7.6) | 0.003 |
[i] Note on Interpretation: For every (n) SD increase in each covariate, we expect the odds of intubation to increase by OR(n) for each respective covariate. For example: after controlling for age, sex, DM, BMI, and symptom duration, for every 78 mg/L (1 SD) increase in CRP, we expect odds of intubation to increase by a factor of 2.81. For every 156 mg/L (2 SD) increase in CRP, we expect odds of intubation to increase by a factor of 2.812=7.90. * Adjusts for age, DM, symptom duration, ethnicity, and BMI. SD = standard deviation, OR = odds ratio, CI = confidence interval, CRP = C-reactive protein, LDH = lactate dehydrogenase, FEU = fibrinogen equivalent units, NLR = neutrophil-lymphocyte ratio, BMI = body mass index, DM = diabetes mellitus.
Fig.1
Kaplan-Meier curves for intubation-free survival of hospitalized CoVID-19 patients stratified by C-reactive protein (CRP). Patients with low CRP (<100 mg/L) have a significantly higher probability of iuntubation-free survival, as compared to patients with high CRP (≥100 mg/L) (p<0.001)
Fig. 2
Predictive model for intubation and mechanical ventilation fit via the Minimax Concave Penalty. (A) Cross-validation deviance indicates optimal model has 3 predictors, including (B) C-reactive protein (CRP), lactate dehydrogenase (LDH), and type 2 diabetes mellitus as most predictive covariates. (C) Cross validated ROC curve of logistic model (CV) along with ROC curve on the validation cohort (EV). (D) Optimal model shown as probability formula where coviariates are centered and scaled using observed mean and standard deviation. DM signifies patient has type 2 diabetes (yes=1, no=0). Both logistic regression and linear approximation formulas presented.