Background. Diabetes mellitus (DM) in patients with COVID-19 is known to be a risk factor for severe disease and death. Hyperglycemia in hospitalized patients with diabetes and COVID-19 is corrected by insulin therapy (IT) in most cases. Studying the effectiveness of IT, the features of IT regimens during hospitalization and the selection of glucose-lowering therapy before discharge of DM2 patients hospitalized with coronavirus infection is relevant.
Objective. Evaluation of the features of compensation of carbohydrate metabolism in hospitalized DM2 patients with coronavirus infection who initially did not receive IT.
Methods. A retrospective study of DM2 patients hospitalized with coronavirus infection who were not receiving IT initially (n=86) was conducted The first group consisted of patients receiving IT in a hospital (n=63), the second group included patients compensated with hypoglycemic non-insulin drugs (n=23). In the study groups, anamnestic, clinical, laboratory and instrumental parameters, and indicators of carbohydrate metabolism were assessed. Additionally, groups receiving glucocorticosteroid (GCS) therapy (n=56) and without it (n=30) was compared.
Results. In inpatient settings, 73.3% of patients were prescribed IT, 38.4% received IT only, 34.9% received IT in combination with other glucose-lowering drugs. Among discharged patients, IT was recommended in 18.8%. Patients receiving IT in the hospital had higher lactate dehydrogenase levels on admission (259.3 vs. 223.8 U/L; P=0.006), and a higher proportion of cases with lung damage greater than 25% (42.9 vs. 13.0%; P=0.011), severe COVID-19 (28.6 vs. 4.4%; P=0.018) and transfer to ICU (19.1 vs. 0.0%; P=0.031). Patients of the first group were characterized by a high level of fasting glycemia on the first (9.6 vs 6.9 mmol/l; P<0.001), third (9.8 vs 7.9 mmol/l; p=0.030) and 7th days (10.4 vs 7.4 mmol/l; p=0.021), the maximum daily dose of insulin was 0.40 (0.19–0.62) U/kg on the 3rd day. The frequency of use of IT in the hospital in patients receiving GCS was 87.5%, in the group without GCS therapy – 46.7% (p<0.001), upon discharge from the hospital – 26.0 and 6.7% (P=0.070), respectively.
Conclusion. In DM2 patients hospitalized with coronavirus infection who did not receive insulin initially, transfer to IT was carried out in 73.3%; at the time of discharge from the hospital, 18.8% needed continued IT. Patients prescribed insulin had severe COVID-19 and worse glycemic control. The use of GCS increased the chance of transfer to IT (87.5%), however, even in patients who did not receive GCS, every second was prescribed IT to compensate for carbohydrate metabolism, which indicates the direct influence of SARS-CoV2 on the development of hyperglycemia in the acute period of coronavirus infection, regardless from the use of GCS.

Keywords: COVID-19, hypoglycemic therapy, glucocorticosteroids, diabetes mellitus, insulin therapy