A Case of Diabetes Mellitus after COVID-19 Vaccination in a Patient with Impaired Glucose Metabolism

Scientific relevance. The clinical features of COVID-19 in patients with comorbidities, including diabetes mellitus (DM), have already been discussed in the medical literature. However, the available data on blood glucose levels in patients with DM during SARS-CoV-2 infection and after COVID-19 vaccination are clearly insufficient to estimate the importance of the changes taking place. Aim. The study aimed to show that patients with DM or impaired glucose metabolism need glycaemic monitoring during COVID-19 disease and after COVID-19 vaccination, drawing on the example of a clinical case. Materials and methods. The study analysed the medical records of a 58-year-old male patient newly diagnosed with DM. He received inpatient and outpatient treatment after COVID-19 vaccination and SARS-CoV-2 infection in February–November 2021. In 2014, the patient was diagnosed with impaired glucose metabolism, including fasting hyperglycaemia (≤ 9 mmol/L), which was corrected by diet. Results. After vaccination with Gam-COVID-Vac component 1 in February 2021, the patient developed polydipsia, polyuria, and arterial hypertension. His laboratory findings were as follows: blood glucose, 25 mmol/L; glycated haemoglobin, 10.7%; fasting insulin, 28.4 μIU/mL; calcium, 2.45 mmol/L; and 25-hydroxyvitamin D, 21 ng/mL. The patient was diagnosed with new-onset type 2 DM, admitted to the endocrinology department of a multidisciplinary hospital, and discharged when his condition stabilised after 14 days of treatment. After vaccination with Gam-COVID-Vac component 2, the patient’s glucose levels did not change. In November 2021, the patient was diagnosed with SARS-CoV-2 infection. Even though all symptoms had resolved within 3 days, the virus persisted in the blood for 12 days without clinical manifestations of the disease. This was confirmed by repeated polymerase chain reaction testing. The patient had moderate hyperglycaemia despite antidiabetic treatment; his glucose levels were restored to normal without hospitalisation. Conclusions. Timely vaccination against COVID-19 in patients with DM, hypertension, and obesity contributes to a mild course of COVID-19 and helps avoid complications in the lungs and other organs. For patients with DM or glucose metabolism disorders, blood glucose monitoring is advisable for detecting and correcting possible hyperglycaemia after vaccination and/or recovery from COVID-19.