Baseline and treatment characteristics
A total of 91 critically ill patients with critical COVID-19 were included in this study. 39 patients (42.9%) were dead and 52 patients (57.1%) were cured and discharged before Mar 22, 2020. The mean age was 63.9 ± 14.1 years (range, 29–85 years), and 52 (57.1%) were male. Baseline characteristics of the survivors and death are shown in Table 1. Overall, there was no significant difference in the proportion of hypertension, diabetes, chronic obstructive pulmonary disease (COPD), first symptoms and respiratory rate between survival group and death group. In addition to common symptoms such as fever, 11% of patients had diarrhea and 4.4% had nausea and vomiting, and one patient in death group has diarrhea as single symptom. The arrhythmic events, such as sinus tachycardia and atrial or ventricular arrhythmia showed no difference between the two groups. Furthermore, there was no significant difference abnormal ST segment and T wave between the two groups. There was no significant difference in the treatment of antiviral drug, Chinese patent drug (XueBiJing/ TanReqing/ YanHuNing) and Methylprednisolone between survival group and death group. However, intravenous immunoglobulin was more common in survivors than in death (p = 0.009).
Table 1
Baseline and treatment characteristics
| All patient (n = 91) | Survival group (n = 52) | Death group (n = 39) | P value |
Clinical characteristics and comorbidities | | | | |
Age(years) | 63.91 ± 14.1 | 59.1 ± 13.2 | 70.4 ± 12.9 | ༜0.001 |
༜50 | 16 (17.6%) | 14 (26.9%) | 2 (5.1%) | 0.011 |
50–69 | 40 (44.0%) | 28 (53.8%) | 12 (30.8%) | 0.028 |
≥ 70 | 35 (38.5%) | 10 (19.2%) | 25 (64.1%) | ༜0.001 |
Male | 52 (57.1%) | 27 (51.9%) | 25 (64.1%) | 0.245 |
Comorbidities | | | | |
Number of comorbidities | | | | |
0 | 42 (46.2%) | 29 (55.8%) | 13 (33.3%) | 0.034 |
1 | 25 (27.5%) | 13 (25.0%) | 12 (30.8%) | 0.542 |
༞1 | 24 (26.4%) | 10 (19.2%) | 14 (35.9%) | 0.074 |
Hypertension | 33 (36.2%) | 15 (28.8%) | 18 (46.2%) | 0.089 |
Coronary heart disease | 12 (13.2%) | 3 (5.8%) | 9 (23.1%) | 0.026 |
Chronic obstructive pulmonary disease | 6 (6.6%) | 2 (3.8%) | 4 (10.3%) | 0.396 |
Diabetes | 9 (9.9%) | 6 (11.5%) | 3 (7.7%) | 0.727 |
Symptoms | | | | |
Fever | 74 (81.3%) | 42 (80.8%) | 32 (82.1%) | 0.877 |
Cough | 42 (46.2%) | 23 (44.2%) | 19 (48.7%) | 0.671 |
Sputum | 14 (15.4%) | 5 (9.6%) | 9 (23.1%) | 0.069 |
Chest congestion | 33 (36.3%) | 20 (38.5%) | 13 (33.3%) | 0.615 |
Dyspnea | 18 (19.8%) | 8 (15.4%) | 10 (25.6%) | 0.224 |
Fatigue | 33 (36.3%) | 15 (28.8%) | 18 (46.2%) | 0.089 |
Diarrhea | 10 (11.0%) | 5 (9.6%) | 5 (12.8%) | 0.629 |
Nausea or vomiting | 4 (4.4%) | 3 (5.8%) | 1 (2.6%) | 0.632 |
Vital signs | | | | |
Respiratory rate(≥30bpm) | 29 (31.9%) | 14 (26.9%) | 15 (38.5%) | 0.242 |
Oxygen saturation(≤93%) | 70 (77%) | 36 (69.2%) | 34 (87.2%) | 0.044 |
Electrocardiogram | | | | |
Sinus tachycardia | 15 (16.5%) | 6 (11.5%) | 9 (23.1%) | 0.227 |
Atrial or ventricular arrhythmia | 10 (11.0%) | 6 (11.5%) | 4 (10.3%) | 0.691 |
Abnormal ST segment and T wave | 19 (20.9%) | 12 (23.1%) | 7 (17.9%) | 0.369 |
Treatment | | | | |
Antiviral drug (Arbidol/ Ribavirin/ interferon α) | 85 (93.4%) | 49 (94.2%) | 36 (92.3%) | 0.715 |
Intravenous immunoglobulin | 56 (61.5%) | 38 (73.1%) | 18 (64.1%) | 0.009 |
Chinese patent drug (XueBiJing/ TanReqing/ YanHuNing) | 77 (84.6%) | 42 (80.8%) | 35 (89.7%) | 0.240 |
Methylprednisolone | 77 (84.6%) | 41 (78.8%) | 36 (92.3%) | 0.140 |
Compared with the survival group, patients in death group were older (70.4 ± 12.9 years vs 59.1 ± 13.2 years, p < 0.001), and more likely to have low Oxygen saturation (≤ 93%, 87.2% vs 69.2%), p = 0.044). Moreover, coronary heart disease (23.1% vs 5.8%) was present more often in non-survival group (p = 0.026).
Laboratory findings
The laboratory findings are shown in Table 2. Baseline lymphocyte count (༜1.1 × 109/L, 84.6% vs 63.5%, p = 0.034), lymphocyte percentage (༜20%, 100% vs 59.6%, p ༜0.001), Platelet count (༜125 × 109/L, 30.8% vs 11.5%, p = 0.026) were significantly lower and white blood cell count (༞9.5 × 109/L, 46.2% vs 13.5%, p = 0.001) and neutrophile granulocyte percentage (༞75%, 67.0% vs 46.2%, p ༜0.001) were significantly higher in non-survivors than survivors. There is an apparent decline glomerular filtration rate (༜90 mL/min, p = 0.005;༜60 mL/min, p = 0.033) in the death group and only 2 of 91 patients had a previous history of renal dysfunction. Furthermore, cellular immunity, such as CD3 T cell count (༜723/µl, 89.7% vs 59.6%, p = 0.002), CD4 T cell count (༜404/µl, 89.7% vs 51.9%, p༜0.001;༜200/µl, 64.1% vs 23.1%, p༜0.001), and CD8 T cell count (༜220/µl, 82.1% vs 51.9%, 32, p = 0.001) were significantly lower in non-survivors than in survivors.
Table 2
| All patient (n = 91) | Survival group (n = 52) | Death group (n = 39) | P value |
Blood routine examination | | | | |
White blood cell count (× 109/L) | | | | |
༞9.5 | 25 (27.5%) | 7 (13.5%) | 18 (46.2%) | 0.001 |
༜3.5 | 16 (17.6%) | 12 (23.1%) | 4 (10.3%) | 0.164 |
Neutrophile granulocyte (༞75%) | 61 (67.0%) | 24 (46.2%) | 37 (94.9%) | ༜0.001 |
Lymphocyte count (༜1.1 × 109/L) | 66 (72.5%) | 33 (63.5%) | 33 (84.6%) | 0.034 |
Lymphocyte (༜20%) | 70 (76.9%) | 31 (59.6%) | 39 (100%) | ༜0.001 |
Haemoglobin (female༜115 g/L,male༜130 g/L) | 34 (37.4%) | 20 (38.5%) | 14 (35.9%) | 0.748 |
Platelet count (༜125 × 109/L) | 18 (19.8%) | 6 (11.5%) | 12 (30.8%) | 0.026 |
Coagulation function | | | | |
Prothrombin time (༞13 s) | 25 (27.5%) | 8 (15.4%) | 17 (43.6%) | 0.003 |
Activated partial thromboplastin time (༞31.3 s) | 19 (20.9%) | 9 (17.3%) | 10 (25.6%) | 0.333 |
D-dimer (µg/mL) | | | | |
༞0.55 | 73 (80.2%) | 35 (67.3%) | 38 (97.4%) | ༜0.001 |
༞1 | 51 (56.7%) | 20 (38.5%) | 31 (79.5%) | ༜0.001 |
Biochemical criterion | | | | |
Creatinine (༞110 µmol/L) | 12 (13.2%) | 5 (9.6%) | 7 (17.9%) | 0.186 |
Glomerular filtration rate (mL/min) | | | | |
༜90 | 34 (37.4%) | 13 (25%) | 21 (53.8%) | 0.005 |
༜60 | 13 (14.3%) | 4 (7.7%) | 9 (23.1%) | 0.033 |
Lactate dehydrogenase (༞250U/L) | 68 (74.7%) | 34 (65.4%) | 34 (87.2%) | 0.018 |
Humoral immunity | | | | |
Immunoglobulin E (༞100 IU/Ml) | 14 (15.4%) | 11 (21.2%) | 3 (7.7%) | 0.083 |
Immunoglobulin M (༞2.3 g/L) | 26 (28.6%) | 11 (21.2%) | 15 (38.5%) | 0.025 |
Immunoglobulin G (༞16 g/L) | 67 (73.6%) | 33 (64.5%) | 34 (87.2%) | 0.011 |
Complement C3 (༜0.9 g/L) | 28 (30.8%) | 13 (25%) | 15 (38.5%) | 0.069 |
Cellular immunity | | | | |
CD3 count (༜723/µl) | 66 (72.5%) | 31 (59.6%) | 35 (89.7%) | 0.002 |
CD4 count (/µl) | | | | |
༜404 | 62 (68.1%) | 27 (51.9%) | 35 (89.7%) | ༜0.001 |
༜200 | 37 (40.7%) | 12 (23.1%) | 25 (64.1%) | ༜0.001 |
CD8 count (༜220/µl) | 59 (31.9%) | 27 (51.9%) | 32 (82.1%) | 0.001 |
Myocardial injury index | | | | |
Creatine kinase MB(༞5 ng/mL) | 27 (29.7%) | 8 (15.4%) | 19 (48.7%) | 0.001 |
Myoglobin (༞110 µg/mL) | 30 (33.0%) | 11 (21.2%) | 19 (48.7%) | 0.006 |
Cardiac troponin (༞0.04 ng/mL) | 31 (34.1%) | 8 (15.4%) | 23 (59.0%) | ༜0.001 |
Other indexes | | | | |
B-type natriuretic peptide precursor | 9 (9.9%) | 2 (3.8%) | 7 (17.9%) | 0.07 |
(༜75y,༞900 pg/mL;≥75y༌༞1800 pg/mL) |
High-sensitivity CRP (༞5 mg/L) | 80 (88.0%) | 42 (80.8%) | 38 (97.4%) | 0.021 |
Procalcitonin (0.1༞ng/mL) | 17 (18.7%) | 4 (7.7%) | 13 (33.3%) | 0.006 |
In the death group, almost all patients (97.4%) have a higher D-dimer level that more than 0.55 µg/mL, and 79.7% patients have a more higher D-dimer level that more than 1 µg/mL, and the percentage significantly elevated than in the survival group (p༜0.001). The non-survivors also presented a higher proportion of increased prothrombin time (p = 0.003), Lactate dehydrogenase (p = 0.022). B-type natriuretic peptide precursor (p = 0.07), high-sensitivity CRP (p = 0.021), and procalcitonin level (p = 0.006) than those survivors. Furthermore, the proportion of abnormal myocardial injury index of death was higher than that of survivors.
Risk factors associated mortality
On multivariate analysis after univariate analysis, D-dimer (༞1 µg/mL, OR = 9.53, 95% CI, 2.53–35.88,), CD4 + T count (༜200/µl, OR = 9.68, 95%CI, 2.76-40.00 ) and cardiac troponin (༞0.04 ng/mL, OR = 5.73, 95% CI, 1.86–17.66) were independent risk factors for mortality. (Table 3)
Table 3
Univariate and multivariate analyses of the clinical variables
| Univariate analysis | | Multivariate analysis |
Odds ratio | 95% CI | P value | Odds ratio | 95% CI | P value |
Clinical characteristic and comorbidities | | | | | | | |
Age | 1.073 | 1.032–1.117 | ༜0.001 | | - | - | - |
Male sex | 1.653 | 0.706–3.872 | 0.247 | | - | - | - |
Hypertension | 2.114 | 0.886–5.405 | 0.092 | | - | - | - |
Coronary heart disease | 4.900 | 1.229–19.543 | 0.024 | | - | - | - |
Laboratory findings | | | | | | | |
White blood cell count (༞9.5 × 109/L) | 5.510 | 1.997–15.207 | 0.001 | | - | - | - |
Lymphocyte count (༜1.1 × 109/L) | 3.000 | 1.058–8.508 | 0.039 | | - | - | - |
High-sensitivity CRP (༞5 mg/L) | 9.048 | 1.106–74.028 | 0.040 | | - | - | - |
APTT (༞31.3 s) | 1.648 | 0.596–4.552 | 0.336 | | - | - | - |
D-dimer (༞0.55 µg/mL) | 18.457 | 2.333-146.015 | 0.006 | | - | - | - |
D-dimer(༞1 µg/mL) | 6.200 | 2.381–16.147 | ༜0.001 | | 9.534 | 2.534–35.875 | 0.001 |
Immunoglobulin G (༞16 g/L) | 3.915 | 1.309–11.108 | 0.015 | | - | - | - |
CD3 count (༜723/µl) | 5.927 | 1.833–19.164 | 0.003 | | - | - | - |
CD4 count (༜404/µl) | 8.102 | 2.518–26.072 | ༜0.001 | | - | - | - |
CD4 count (༜200/µl) | 5.952 | 2.375–14.918 | ༜0.001 | | 9.678 | 2.755–33.999 | ༜0.001 |
Procalcitonin (༞0.1 ng/Ml) | 5.500 | 1.622–18.649 | 0.006 | | - | - | - |
Myoglobin (༞110 µg/mL) | 3.541 | 1.418–8.841 | 0.007 | | - | - | - |
Cardiac troponin (༞0.04 ng/mL) | 7.906 | 2.946–21.218 | ༜0.001 | | 5.725 | 1.857–17.656 | 0.002 |
Glomerular filtration rate (༜90 mL/min) | 3.500 | 1.439–8.515 | 0.006 | | - | - | - |
Lactate dehydrogenase (༞250U/L) | 3.600 | 1.2-10.804 | 0.022 | | - | - | - |
Intravenous immunoglobulin | 3.34 | 0.161–0.932 | 0.034 | | | | |