Baseline characteristics between short-term and long-term hospital stay
Detail comparison of characteristics in short-term and long-term group were presented in Table 1. The mean age in long-term stay was 55.1 years, significantly older than those in short-term stay(P = 0.01). Most patients had an exposure history in both group (87%, 95/109), but smaller current smoker (8.2%, 9/109). Hypertension was the most common comorbidity (34%, 21/61), followed by diabetes (15%,9/61) and Cardiopathy (8%, 5/61). The most common symptoms were fever and cough, followed by fatigue and Vomiting.
Table 1
Demographic, clinical and laboratory findings of COVID-19 patients
Characteristic | Short-term hospital stay (≤ 10 days) (n = 61) | Long-term hospital stay (> 10 days) (n = 48) | P value |
Demographics Characteristic |
Age, years | 46.4 ± 12.1 | 55.1 ± 11.5 | 0.01 |
Sex | | | |
Male | 41 (67.2%) | 32 (66.7%) | 1 |
Female | 20 (32.8%) | 16 (33.3%) | |
Height | 1.6 ± 0.1 | 1.62 ± 0.15 | 0.476 |
Weight | 62.3 ± 11.4 | 64.7 ± 10.7 | 0.451 |
BMI | 23.2 ± 3.1 | 24.0 ± 3.4 | 0.261 |
Exposure history | 52(85.2%) | 43(89.6%) | 0.701 |
Current smoker | 8(13.1%) | 1(2.1%) | 0.084 |
Clinical Characteristic |
Diabetes | 6(9.8%) | 3(6.2%) | 0.745 |
Hypertension | 11(18%) | 10(20.8%) | 0.902 |
Cardiopathy | 2(3.3%) | 3(6.2%) | 0.783 |
COPD | 1(1.6%) | 1(2.1%) | 1 |
Tuberculosis | 1(1.6%) | 0 | 1 |
Carcinoma | 2(3.3%) | 0 | 1 |
Chronic kidney disease | 0 | 1(2.1%) | 0.923 |
Chronic liver disease | 3(4.9%) | 1(2.1%) | 0.788 |
Respiratory rate | 18.1(0.7%) | 17.5(1.0%) | 0.321 |
Fever(temperature ≥ 37.3℃) | 43 (70.5%) | 35 (72.9%) | 0.948 |
Cough | 28 (45.9%) | 26 (54.2%) | 0506 |
Fatigue | 12 (19.7%) | 10 (20.8%) | 1 |
Vomiting | 14 (23.0%) | 11 (22.9%) | 1 |
Hemoptysis | 2(3.3%) | 3(6.2%) | 0.904 |
Chest pain | 4(6.6%) | 5(10.4%) | 0.707 |
Digestive Symptoms | 4(6.6%) | 4(8.3%) | 1 |
Time from onset to admission | 5.5 ± 3.5 | 6.5 ± 4.0 | 0.232 |
Laboratory findings |
WBC, 103/mm3 | 4.8 ± 0.3 | 4.3 ± 0.4 | 0.015 |
Neutrophils, 103/mm3 | 3.3 ± 1.4 | 4.1 ± 3.2 | 0.138 |
Hemoglobin, g/L | 135.6 ± 13.1 | 128.0 ± 22.3 | 0.036 |
Lymphocyte, 103/mm3 | 1.3 ± 0.5 | 1.3 ± 0.9 | 0.739 |
Monocyte, 103/mm3 | 0.3 ± 0.01 | 0.4 ± 0.03 | 0.028 |
MLR (Monocyte Lymphocyte ratio) | 0.28 ± 0.05 | 0.32 ± 0.03 | 0.030 |
Platelet count, 109/L | 212.9 ± 75.4 | 207.2 ± 67.7 | 0.681 |
Troponin, ng/mL | | | |
> 28 | 22(36.1%) | 20(41.7%) | 0.691 |
D-dimer, µg/L | 0.4 ± 0.1 | 0.5 ± 0.3 | 0.231 |
ESR, mm/Hour | 65.6 ± 8.7 | 60.4 ± 5.1 | 0.191 |
Hypersensitive CRP, mg/L | 17.4 ± 3.1 | 20.7 ± 1.8 | 0.024 |
LDH | 225.8 ± 17.1 | 212.4 ± 6.2 | 0.159 |
ALT | 24.9 ± 4.5 | 28.6 ± 3.1 | 0.320 |
Procalcitonin, ng/ml | 0.03 ± 0.01 | 0.035 ± 0.02 | 0.233 |
IL-2, pg/mL | 1.1 ± 0.7 | 1.9 ± 0.8 | 0.186 |
IL-4, pg/mL | 2.0 ± 0.7 | 2.1 ± 0.8 | 0.473 |
IL-6, pg/mL | 6.7 ± 2.3 | 9.1 ± 1.7 | 0.165 |
IL-10, pg/mL | 3.4 ± 2.0 | 4.9 ± 1.8 | 0.115 |
ESR: erythrocyte sedimentation rate; LDH: lactate dehydrogenase; ALT: alanine aminotransferase; WBC: white blood cells; IL: interleukin; CRP: C-reactive protein. |
In blood routine tests, The WBC, Hemoglobin were decreased, and Monocyte, MLR (Monocyte Lymphocyte ratio) and Hypersensitive CRP were all increased in long-term stay (P = 0.015, P = 0.036, P = 0.028, P = 0.03 and P = 0.024, respectively). There was no statistical difference between Neutrophils, Lymphocyte, Platelet count, Troponin, lactate dehydrogenase (LDH), interleukin (IL), et al (P > 0.05, Table 1).
Five treatment strategies were used in the hospital, including Resochin, Lopinavir, Arbidol, Recombinant Human Interferon, Hormonotherapy and Human immunoglobulin (Table 2). Lopinavir (100%) and recombinant Human Interferon (almost 100%) were most used in two groups. More patients were treated with Resochin and Human immunoglobulin in short-term hospital stay compared to long-term stay(P < 0.001).
Table 2
Treatments of COVID-19 patients in two groups
Characteristic | Short-term hospital stay (≤ 10 days) (n = 61) | Long-term hospital stay (> 10 days) (n = 48) | P value |
Treatments |
Resochin | 45(73.8%) | 37(77.1%) | < 0.001 |
Lopinavir | 61(100.0%) | 48 (100.0%) | 0.213 |
Arbidol | 55(90.2%) | 47 (97.9%) | 0.212 |
Recombinant Human Interferon | 61(100.0%) | 47 (97.9%) | 0.904 |
Hormonotherapy | 6 (9.8%) | 8(16.7%) | 0.441 |
Human immunoglobulin | 44(72.1%) | 31(68.9%) | < 0.001 |
Time from onset to fever | 1.0 ± 1.0 | 1.0 ± 1.0 | 0.360 |
Time from onset to cough | 2.0 ± 1.0 | 1.0 ± 1.0 | 0.190 |
Time from onset to COVID-19 negative | 7.0 ± 4.0 | 20.0 ± 6.0 | < 0.001 |
Time from onset to discharge | 9.0 ± 3.0 | 21.5 ± 7.0 | < 0.001 |
So, significant differences between the groups were found for patient’s age, blood routine markers (WBC, Hemoglobin, Monocyte and MLR), treatment scheme (Resochin and Human immunoglobulin), the mean time from illness onset to COVID-19 negative, 7 days in short-term stay and 20 days in long-term stay. The mean time from onset to discharge was 9.0 days in short-term stay and 21.5 days in long-term stay (Table 2).
Identifying Independent Risk Factors for short-term and long-term hospital stay
Clinical variables including age, blood routine markers (WBC, Hemoglobin, Monocyte, MLR and CRP), were included in the univariable analysis. As shown in Table 3, all above parameters except Hemoglobin were independent predictors associated with higher risk of long-term hospital stay. Multivariate logistic regression analysis showed that MLR and CRP were significantly correlated with long-term stay for COVID-19 patients (HR = 2.03, 95%CI = 1.02–5.39; P = 0.022 and HR = 1.32, 95%CI = 1.05–3.24, P = 0.045, respectively, Table 3).
Table 3
Risk factors associated with long-term hospital stay of COVID-19 patients
Variables | Univariable | Multivariable |
OR (95%CI) | P value | OR (95% CI) | P value |
Age, years | 1.09(1.01–1.21) | 0.047 | NA | NA |
WBC | 1.12(1.09–1.35) | 0.028 | NA | NA |
Hemoglobin | 1.03(0.96–1.06) | 0.053 | NA | NA |
MLR | 2.65(1.64-11) | 0.016 | 2.03(1.02–5.39) | 0.022 |
CRP | 1.58(1.04–3.68) | 0.038 | 1.32(1.05–3.24) | 0.045 |
The Accuracy, AUC, sensitivity, specificity of MLR for predicting long-term hospital stay were 0.7, 0.72,68.9% and 70.8%, respectively (Table 4 and Fig. 1), with the optimal cutoff value 0.31. The optimal cutoff value of CRP was 19.3 mg/L. The Accuracy, AUC, sensitivity, specificity was 0.69,0.67, 65.6% and 72.9%, respectively (Table 4 and Fig. 2).