To evaluate mortality and risk factors for death in patients with COVID-19 who required admission to intensive care units (ICU) for respiratory support in Russia.
Material and methods
In a retrospective study, we collected medical records of the consecutive ICU patients submitted by the local COVID-19 hospitals across Russia to the Federal Center at the Sechenov University (Moscow) between 36 March 16 to May 3, 2020. All patients have completed their hospital stay (death or recovery). Diagnosis of SARS-CoV-2 pneumonia was established both by polymerase chain reaction (PCR) and CT. In patients with inconclusive or negative results of PCR, the SARS-CoV-2 pneumonia was defined as severe acute respiratory infection with typical CT findings and no other obvious aetiology. We used Cox proportional hazards regression model adjusted for age, sex and other risk factors to estimate hazard ratios (HR) and 95% confidence intervals (CI).
We studied 1522 ICU patients with SARS-CoV-2 induced acute respiratory distress syndrome (ARDS), including 864 males and 658 females at the median age of 62 years. Nine hundred twenty two records (60.1%) were submitted from Moscow and Moscow province, and 600 records (39.4%) were received from the hospitals located in 70 regions of Russia. SARS-CoV-2 was verified by PCR in 995 (65.4%) patients. Among 1522 patients enrolled in the study, 995 patients (65.4%) died, and 527 (34.6%) patients recovered. The most common causes of death were ARDS (93.2%), cardiovascular events (3.7%) and pulmonary embolism (1.0%). The mortality rate was low in patients with less severe pneumonia requiring oxygen therapy (10.1%). However, it increased significantly in patients who were placed on noninvasive or invasive ventilation (36.8% and 76.5%, respectively). Risk of death increased with age, and in males older than 50 years it was significantly higher than in females of similar age. In a unvariate analysis, arterial hypertension, coronary artery disease (CAD), history of stroke, atrial fibrillation, type 2 diabetes, obesity and malignancies were associated with an increased risk of death. However, only CAD (HR 1.257, 95% CI 1.064-1.485, p=0.007), type 2 diabetes (HR 1.300, 95% CI 1.131-1.494, p<0.0001) and obesity (HR1.347, 95% CI 1.166-1.556, p<0.0001) retained statistical signicance in multiple factor analysis.
In ICU patients with COVID-19, severity of ARDS (i.e. requirement in mechanical ventilation), age, male gender, CAD, obesity and type 2 diabetes were associated with a higher risk of death.
COVID-19, respiratory support, ICUs, mortality, risk factors.