By April 5, 2020, 52 patients were admitted to B-ICU of Wuhan Leishenshan hospital. After excluding 5 patients without confirmed SARS-CoV-2 RNA or without complete information, we finally included 47 inpatients in this study (Table 1). The mean age was 70.55 ± 12.52 years (range 38 ~ 93 years). Among all included patients, 30 (63.8%) patients were male. Comorbidities were present in 40 (68.1%) patients, with hypertension being the most common comorbidity (n = 25 [53.2%]), followed by diabetes (n = 18 [38.3%]), and chronic kidney disease (n = 15 [31.9%]). The median APACHE II score of all patients was 18.6 ± 7.79. A total of 34 (72.3%) patients had findings of bilateral infiltrates on radiographic imaging.
Differences Of Clinical Characteristics Between Survivors And Non-survivors
The median SOFA score of non-survivors (7, IQR 5–9) was much higher than that of survivors (3, IQR 1–6). The median lymphocyte count of ICU patients was 0.77 × 109/L (IQR 0.54–1.29), which was 0.54 × 109/L (IQR 0.26–0.63) in non-survivors. Concentrations of C-reactive protein, procalcitonin, interleukin-6 (IL-6) and interleukin-1B (IL-1B) were significantly higher in non-survivors than those in survivors. Compared with survivors, non-survivors were more likely to develop septic shock (6 [40%] vs 3 [9.4%]), and disseminated intravascular coagulation (3 [21.4%] vs 0).
For the primary outcome, 15 (31.9%) of 47 patients died in our study. ARDS (12; 25.5%), acute cardiac injury (12; 25.5%), acute kidney injury (10; 21.3%), were frequently observed in ICU patients. Three patients developed bloodstream infections during hospitalization, of which Klebsiella pneumoniae, Staphylococcus aureus and Enterococcus faecalis were identified. Invasive mechanical ventilation was performed to 13 (27.7%) patients, 9 of whom died. The median duration from admission to invasive mechanical ventilation and invasive mechanical ventilation to death were 6.0 (2.00–11.00) days, and 5.54 ± 5.98 days respectively. Two patients received extracorporeal membrane pulmonary oxygenation (ECMO) as rescue therapy, one of whom survived. Forty-five (95.7%) patients received intravenous antibiotics and 11 (23.4%) received systematic corticosteroid. Three patients (6.4%) received COVID recovery patient plasma treatment who all survive (Table 1).
Risk Factors Of Mortality
Univariate analysis revealed that variables of APACHE II, CURB-65, SOFA, ARDS, chronic heart disease, septic shock, lymphocyte count, neutrophil count were associated with death (table 2). In the multivariable logistic regression model, we found that SOFA score (OR = 1.47, 95% CI = 1.01–2.13, P = 0.04) and lymphocyte count at admission (OR = 0.02, 95% CI = 0.00-0.86, P = 0.04) were independent factors related to mortality (Table 2)
Predictive value of lymphocyte count and SOFA for survival
Baseline lymphocyte count was significantly higher in survivors than non-survivors. In survivors, lymphocyte count was lowest on admission and improved during hospitalization, whereas decreased continuously until death in non-survivors (Fig. 1).
AUC of lymphocyte count statistically significant in the group of survivors or non-survivors (AUC 0.865; 95% CI, 0.375–0.781; P < 0.0001). Optimal cutoff value of lymphocyte count was 0.63 × 109/L. Patients with higher lymphocyte count (> 0.63 × 109/L) on admission had a significantly well prognosis than those with lower lymphocyte count (≤ 0.63 × 109/L) in overall survival (P = 0.001) (Fig. 2).
AUC of SOFA score statistically significant in the group of survivors or non-survivors (AUC 0.860; 95% CI, 0.728–0.944; P < 0.0001). Optimal cutoff value of SOFA score was 4. Patients with lower SOFA score ≤ 4 on admission had a significantly well prognosis than those with higher SOFA score > 4 in overall survival (P = 0.001) (Fig. 3).