Filenews 18 May 2021
The COVID-19 pandemic, caused by the SARS-CoV-2 coronavirus, has caused enormous pressure on global health systems while leading to an ever-increasing number of victims. At the same time, for years, another epidemic has been taking place and is none other than Diabetes Sugar, which affects about 10% of the world's population and is now a well-documented risk factor for severe COVID-19 disease and an increase in mortality of up to 50%. New data, however, also suggest the negative effect of the disease on glycaemic control of diabetic patients, indicating that the association of the two diseases is two-way and quite complex.
Why are people with diabetes mellitus more vulnerable to COVID-19 infection and have an increased risk of adverse development?
The reasons why diabetes is considered a risk factor for worse clinical outcome of COVID-19 are now quite well thought out. First of all, it is known that diabetic patients are more prone to infections due to disturbed immune response with disturbances in the function of macrophages and T lymphocytes. This spread is even more pronounced with regard to respiratory infections, as diabetes is often accompanied by functional disorders of the lungs such as reduced lung volume and obstruction of peripheral airways, which further reduce the defence against various pathogens. It has been shown that the main mechanism of entry of SARS-CoV-2 into respiratory cells is through the receptor of the conversion enzyme angiotensin 2 (ACE2), an enzyme expressed in various organs and has a known anti-inflammatory and antioxidant role. In patients with diabetes, the expression of this enzyme in the lung is increased, which probably facilitates the entry of the virus into the body and subsequent infection.
As has already been shown from the early stages of the pandemic, severe COVID-19 disease is a hyper-inflammatory condition, characterized by the so-called "cytokine storm", an over-secretion of molecules with inflammatory action that can rapidly lead to multi-organic deficiency. Diabetes is a condition of chronic low degree of inflammation, which is associated with insulin resistance and the accumulation of visceral fat. When infected with SARS-CoV-2, it is easy for this chronic subclinical inflammation to be diverted faster to the cataclysmic inflammation that induces severe disease. Diabetes is also associated with increased platelet accumulation, conditions that lead to hyperglycaemia. Necrotic studies in patients with COVID-19 have shown an increased incidence of thrombosis and vascular damage outside the respiratory system, so it is reasonable to assume that diabetic patients are at greater risk for vascular events when infected with SARS-CoV-2. Finally, the co-morbidities that often accompany diabetes, such as obesity, arterial hypertension and cardiovascular disease, are through various mechanisms independent risk factors for heavier disease and increased mortality from COVID-19.
Regulation of diabetes mellitus in people suffering from COVID-19
On the other hand, SARS-CoV-2 itself can worsen the regulation of diabetes. The infection itself causes the release of countervailing hormones, such as cortisol and catecholamines, which cause hyperglycaemia, while a similar effect can cause some of the treatment regimens used during hospitalization, such as glucocorticoids. This deregulation can also induce the onset of acute complications of diabetes, such as diabetic ketoacidosis, with the risk of being greater in patients with type 1 diabetes mellitus, especially children and adolescents, while problematic access to health services during the pandemic can lead to a delayed diagnosis of this complication with fatal results. Even more strikingly, some recent data have shown a correlation of infection with SARS-CoV-2 with first occurrence of diabetes mellitus in previously healthy individuals.
Factors affected by the COVID-19 epidemic leading to the deregulation of diabetes mellitus
The deterioration of glycaemic control from COVID-19 disease also plays a major role in both the psychology part and the daily practical difficulties that arose during the pandemic. Diabetic patients are more prone to mental disorders such as anxiety disorder and depression, factors that are documented to exacerbate diabetic complications, both due to pathophysiological pathways and due to poor self-care of patients. The disruption of social relations as a result of the restriction measures imposed worldwide leads many diabetic patients to increased dysthymia by neglecting regular self-control at the level of glucose measurements during the day, as well as overconsumption of inappropriate foods with consequent hyperglycaemia and weight gain. At the same time, the difficulty of access to the health system at the level of outpatient clinics leads to problematic and incomplete communication with the attending physician and therefore insufficient control of diabetes, while long delays in supplies of materials during the lockdown period often resulted in shortages of necessary materials for the daily self-control of patients such as glucose measuring strips resulting in poor self-control.
In conclusion, the relationship between diabetes mellitus and COVID-19 is two-way and multi-layered. Diabetic patients make up a particularly vulnerable part of the population, as diabetes mellitus is a risk factor for severe COVID-19, but COVID-19 infection can deregulate diabetes mellitus. This particular population group should therefore pay particular attention to the pandemic, which will protect them from dangerous complications, while protecting health systems from frequent and severe hospitalizations. Finally, vaccination of all is the only way to protect vulnerable groups and tackle the pandemic.
Athanasios Raptis, is Associate Professor of Pathology-Sugar Diabetes EKPA, 2nd Pedagogical Pathological Clinic-Research Unit and Diabetic Center, P.G.N. "ATTICON"
