Early Warning Factors of Death in COVID-19 Patients

The infectious coronavirus disease 2019 (COVID-19) has spread all over the world and been persistently evolving so far. The number of deaths in the whole world has been rising rapidly. However, the early warning factors for mortality have not been well ascertained. In this retrospective, single-centre cohort study, we included some adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Renmin Hospital of Wuhan University who had been discharged or had died by Apr. 8, 2020. Demographic, clinical and laboratory data at admission were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable analysis, Cox proportional hazard model analysis and receiver operating characteristic (ROC) curve to explore the early warning factors associated with in-hospital death. A total of 159 patients were included in this study, of whom 86 were discharged and 73 died in hospital. Hypertension (52.1% vs. 29.1%, P=0.003) and coronary heart disease (28.8% vs. 12.8%, P=0.012) were more frequent among non-survived patients than among survived patients. The proportions of patients with dyspnoea (67.1% vs. 25.6%, P<0.001), chest distress (58.9% vs. 26.7%, P<0.001) and fatigue (64.4% vs. 25.6%, P<0.001) were significantly higher in the non-survived group than in the survived group. Regression analysis with the Cox proportional hazards mode revealed that increasing odds of in-hospital death were associated with higher IL-6 (odds ratio 10.87, 95% CI 1.41-83.59; P=0.022), lactate (3.59, 1.71-7.54; P=0.001), older age (1.86, 1.03-3.38; P=0.041) and lower lymphopenia (5.44, 2.71-10.93; P<0.001) at admission. The areas under the ROC curve (AUCs) of IL-6, lymphocyte, age and lactate were 0.933, 0.928, 0.786 and 0.753 respectively. The AUC of IL-6 was significantly higher than that of age (z=3.332, P=0.0009) and lactate (z=4.441, P<0.0001) for outcome prediction. There was no significant difference between the AUCs of IL-6 and lymphocyte for outcome prediction (z=0.372, P=0.7101). It was concluded that the potential risk factors of higher IL-6, lactate, older age and lower lymphopenia at admission could help clinicians to identify patients with poor prognosis at an early stage.