Comorbidities and predicting the outcome of COVID-19: the treatment results of 13,585 patients hospitalized in the Moscow Region

Background: The COVID-19 pandemic is seriously affecting the society and economy of many countries, including the Russian Federation. Identifying of the major risk factors for an unfavorable outcome could help save lives and reduce the disease burden. Until now, no results of the studies on this issue based on the Russian clinical material have been published. Aim: To evaluate the effects of comorbidities on the outcome (discharge or hospital death rates) in patients hospitalized with a diagnosis of COVID-19.

Materials and methods: We analyzed a database of 13,585 patients who were treated in 66 hospitals functioning under the obligatory health insurance system of the Moscow Region, with a final diagnosis of "COVID-19, virus identified" (ICD 10 code U07.1) from April 1, 2020 to June 23, 2020 (53.7% women, 46.3% men, mean (± SD) age 56.5 ± 14.9 years (median 57 [46; 67])). In all patients, the diagnosis of COVID-19 was confirmed by polymerase chain reaction (PCR) for the SARS-CoV-2 virus in nasopharyngeal or oropharyngeal swabs. 93.8% of the patients showed signs of interstitial viral pneumonia (87.9% confirmed by computed tomography of the lungs, 5.9% by standard chest X-ray). All patients received the standard treatment according to the "Temporary Guidelines on prevention, diagnosis and treatment of the new coronavirus infection (COVID-19), version 7 (03.06.2020)” from the Ministry of Health of the Russian Federation. 1518 (11.2%) patients had at least one comorbid condition, the most frequent being arterial hypertension (AH), ischemic heart disease (IHD), and diabetes mellitus (DM). In 71 female patients, COVID-19 occurred during pregnancy. By June 23, 2020, 10761 (79.2%) patients have been discharged from hospitals with recovery, improvement, or stabilization (the latter was considered a conditionally favorable outcome). 1246 patients died, that transfers into the in-hospital death rates of about 9.2% (unfavorable outcome). The rest of 1578 (11.6%) patients continued their treatment, or were transferred to other medical units for the continuation of care. The comparative analysis included patients (total, n = 12,007) with favorable (n = 10,761) and unfavorable (n = 1246) inpatient outcomes. The age-adjusted Charlson index was used to quantify the severity of comorbidity.

Results: In the patients without any comorbidity, the in-hospital death rate was 9.4%. At least one comorbidity increased the incidence of unfavorable outcome to 13.9% (p < 0.001), and multiple comorbidities to 24.8% (p < 0.001). The following specific conditions significantly increased the likelihood of an unfavorable outcome (p < 0.05): DM, mental disorders, morbid obesity, IHD, AH, stroke (including past history), myocardial infarction (including past history), chronic heart failure, heart arrhythmias, cancer, and chronic kidney disease. Tuberculosis, HIV/AIDS, trauma / surgical disorders, and pregnancy were not associated with higher rates of unfavorable outcomes, but these patients were significantly younger than patients without comorbidities and with comorbidities with higher death rates. The age-adjusted Charlson index of > 3 was associated with a more than 2-fold increase in the in-hospital death rates (25.2%, p < 0.001).

Conclusion: Comorbidity is one of the drivers in the prognosis of in-hospital death rates in patients with COVID-19. However, it should be considered in the context of the patient age-related characteristics. The Charlson Age-Adjusted Comorbidity Index is a useful tool for assessment of the COVID-19 prognosis. The prognosis should be considered serious at a score of 3 or more.