**History of the issue**

Already in the initial period of studying the prognostic significance and danger to human health and life of the state of infection with the COVID-19 virus in January–April 2020, mainly thanks to research from Chinese medical centers, it was clarified that factors contributing to lung damage are highly likely the course of the disease in severe form, include: advanced age [6]; diabetes [6, 7, 24]; obesity [25]; chronic lung diseases [14], including asthma [12]; heart disease [12, 16]; hypertension [14]; chronic kidney disease [14].

In one of the first clinical observations of 41 COVID-19-infected people in Wuhan, China, it was shown that in 32% of cases, COVID-19 was combined with other diseases, including diabetes (20%), hypertension (15%) and cardio-vascular diseases (15%), [16]. Another report of patients who were discharged or died at clinics in Wuhan between January 1, 2020 and March 8, 2020 reported that patients with COVID-19 with diabetes had worse outcomes compared to patients of the same sex and age without diabetes. Advanced age and concomitant arterial hypertension independently contributed to the hospital death of patients with diabetes [6]. The results obtained at the Wuhan Jin Yin Tang Hospital showed that in intensive care units, 17% of patients suffered from chronic diseases, including diabetes (17%), cerebrovascular diseases (13.5%), chronic heart disease (10%) and T. D. During treatment in 35% of critically ill patients, hyperglycemia was a concomitant pathology, and mortality among patients with diabetes was 77.7% [16, 26].

In a retrospective study of 138 patients with COVID-19, from a clinic in this city in China, published on February 7, 2020, it was shown that 46.4% of patients had one or more comorbidities, of which 10% had diabetes, while in wards Intensive care (ICU) 22.2% of patients had diabetes, that is, 2 times more often [26]. The study of the relationship between diabetes and mortality and severity of COVID-19, as well as in determining the prevalence of diabetes in patients with COVID-19, has also been conducted in several meta-analyzes. Employees from the Institute of Gastroenterology, Delhi, India (Institute of Liver, Gastroenterology, & Pancreatico-Biliary Sciences, Sir Ganga Ram Hospital, New Delhi, India). searched PubMed for case–control studies in English published between January 1 and April 22, 2020 that had data on diabetes in patients with COVID-19. The incidence of diabetes was compared between patients with and without a combined mortality or severity endpoint. Included 33 studies (16,003 patients). The authors found that diabetes was significantly associated with mortality from COVID-19 with a pooled odds ratio of 1.90 [24]. Another meta-analysis conducted by researchers at the Faculty of Medicine, Universitas Pelita Harapan, Tangerang, Indonesia analyzed data from 6452 patients from 30 studies. A meta-analysis showed that diabetes was associated with an incidence of combined adverse outcomes (relative risk, RR 2.38) and its subgroup, which included mortality (RR 2.12), severe COVID-19 (RR 2.45), acute respiratory distress syndrome (ARDS) (RR 4.64) and disease progression (RR 3.31). It was concluded that diabetes was associated with mortality, severe COVID-19, ARDS and disease progression in patients with COVID-19 [7].

From the statistics of the 2020 epidemic in the North American continent, it follows that diabetes mellitus can increase the risk of death from COVID-19 by 12 times, according to the portal of the US Centers for Disease Control and Prevention. Patients infected with coronavirus with diabetes are six times more likely to need hospitalization for inpatient treatment, and diabetes is in second place in terms of severity of complications in COVID-19 after cardiovascular disease [10]. According to the China Cardiometabolic and Cancer Cohort (4C) nationwide study, compared with patients with normal glucose tolerance, people with impaired glucose tolerance or diabetes had a high risk of lung infection with a multifactorial adjusted odds ratio (OR; 95% CI) 1.56 (1.02–2.37) and 1.63 (1.01–2.61), respectively [27]. Epidemiological evidence from the United States suggests that diabetes is associated with a high risk of infectious disease. People with diabetes are at increased risk of bacteremic pneumococcal infection and are reported to have a high risk of nosocomial bacteremia with mortality rates up to 50% [28]. At the same time, the state of carbohydrate metabolism in patients with COVID-19 who have not previously suffered from diabetes has not been sufficiently studied in clinical studies. Hyperglycemia, even in people with no previous diabetes, has often been observed in complicated coronavirus disease 2019 (COVID-19), [17, 18]. Hyperglycemia in COVID - 19 is a strong predictor of a worse prognosis and an increased likelihood of death [18]. In the above-cited study of patients with COVID-19, conducted at the Wuhan Jin Yin Tang Hospital, with the participation of 99 infected people, it was shown that 52% of those infected had elevated glucose levels, and in some patients with viral pneumonia, infection with the virus was accompanied by an increase in the concentration glycated hemoglobin [16].

## **Goal and tasks**

To assess the incidence of hyperglycemia and diagnosis of newly diagnosed diabetes mellitus in patients with COVID-19 and acute lung damage at the age of 41–80 years, hospitalized in a repurposed infectious diseases hospital in Moscow with a diagnosis of pneumonia.

#### **Material and methods**

The observational study analyzed laboratory and clinical diagnostic data of 278 patients who did not have, according to the anamnesis and the presented medical reports, signs of impaired glucose tolerance and manifest forms of diabetes mellitus, including 163 men and 115 women aged 41–80 years admitted to hospital for diagnosis and treatment in the period from 12.04.2020 to 10.11.2020 with diagnoses according to ICD-10: U07.1 Coronavirus infection. In the selected groups of patients, the initial and subsequent levels of fasting blood glucose were analyzed, after 8 hours without food, on a stationary automatic analyzer and using portable glucometers using diagnostic test strips. The concentration of glucose and ketones in urine was determined by a semi-quantitative method. The dynamics of indicators was assessed when pathological values of glucose concentration were detected. Glucose levels above 6.4 mmol/L were considered pathological.

### **Results**

In patients aged 41–80 years hospitalized with covid-19 infection and pneumonia, fasting hyperglycemia was diagnosed in 31–47%, glucosuria in 1.9–6.1%, ketonuria - 20.4-46.2% of cases, in different age groups. In 16.6–31.3% of cases in patients with covid-19, after treatment and regression of changes in the lungs, there was a

*Frequency of Hyperglycemia in Patients with Covid-19 Infection and Pneumonia DOI: http://dx.doi.org/10.5772/intechopen.96306*

normalization of glucose levels, but in 14.8–16.7% of cases persisted, and in 9–13% of them, after an additional study, newly diagnosed diabetes mellitus was diagnosed. Hyperglycemia was significantly more often detected in patients with arterial hypertension of 2–3 degrees of severity and with a tendency to reliability, in patients with obesity 2–3 degree. Lipid metabolism disorders (hypertriglyceridemia and hypercholesterolemia), characteristic of changes in carbohydrate metabolism with impaired glucose tolerance and diabetes, were significantly more often diagnosed in patients with covid-19 than in the group of patients with acute and chronic lung pathology without proven infection with this virus, but only in the group of patients age period 41–60 years.
