Blood sugar, or glucose, is the primary energy source for the body’s cells, requiring careful regulation. The COVID-19 pandemic revealed a complex relationship between SARS-CoV-2 infection and glucose management. The virus complicates the health of individuals with existing diabetes and may trigger the onset of the condition in previously healthy people. This systemic impact extends beyond the respiratory system, making understanding this metabolic disruption essential for managing both acute illness and long-term recovery.
How COVID-19 Affects Existing Diabetes Management
For individuals already diagnosed with Type 1 or Type 2 diabetes, a COVID-19 infection significantly challenges glucose control. Acute illness increases stress hormones like cortisol and adrenaline, causing the liver to release more glucose into the bloodstream. This surge leads to severe hyperglycemia, or high blood sugar, even in those whose diabetes was previously well-controlled.
Systemic inflammation from the viral infection promotes insulin resistance, where the body’s cells do not respond effectively to available insulin. These factors place diabetic patients at increased risk for severe COVID-19 outcomes, including hospitalization and death. Poor glycemic control, defined by elevated glycosylated hemoglobin (HbA1c), is associated with a higher likelihood of developing severe symptoms and long-term complications, often referred to as Long COVID.
An acute infection can quickly spiral into life-threatening metabolic emergencies like diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS). DKA occurs when the body produces high levels of blood acids called ketones; it is more common in Type 1 diabetes but can affect Type 2 patients during severe illness. HHS involves extreme dehydration and severely high blood sugar without significant ketosis, frequently seen in older adults with Type 2 diabetes. The incidence of both DKA and HHS increased during the pandemic, underscoring the acute metabolic danger the virus poses.
The Link Between COVID-19 and New Diabetes Diagnoses
Research shows that SARS-CoV-2 infection can lead to a diabetes diagnosis in individuals with no prior history. Epidemiological data indicates a higher incidence of new diabetes diagnoses in the months following COVID-19 recovery compared to those who did not contract the virus.
It is unclear whether the virus directly causes the disease or simply unmasks a pre-existing, undiagnosed condition. Many new diagnoses likely represent previously unrecognized Type 2 diabetes, where the physiological stress of the infection pushed individuals with underlying insulin resistance past the diagnostic threshold. However, reports also suggest the virus may trigger an autoimmune response, leading to new-onset Type 1 diabetes, particularly in children and adolescents.
Global registries found that new-onset hyperglycemia persisted beyond the resolution of the acute infection in a notable percentage of patients. This supports the theory that the virus may have a direct or lasting effect on glucose metabolism, rather than the hyperglycemia being solely a temporary stress response. This link suggests continued vigilance regarding metabolic health in all COVID-19 survivors.
Biological Mechanisms of Glucose Changes
The SARS-CoV-2 virus can alter glucose metabolism through several pathways. One major mechanism is the inflammatory response, often termed a “cytokine storm,” which leads to systemic insulin resistance. Pro-inflammatory cytokines, such as IL-6, interfere with insulin signaling, causing cells to become less responsive to insulin and driving blood sugar levels upward.
The virus also appears to directly attack the pancreas, the organ responsible for producing insulin. SARS-CoV-2 gains entry into human cells by binding to the ACE2 receptor, which is expressed on the insulin-producing beta cells. Viral infection may cause damage, dysfunction, or death of these beta cells, reducing the body’s ability to produce insulin.
A common treatment for severe COVID-19, the use of corticosteroids like dexamethasone, is a powerful contributor to high blood sugar. These medications cause “steroid-induced hyperglycemia” by increasing glucose production in the liver and worsening insulin resistance. This effect often necessitates temporary insulin therapy, even in patients who have never had diabetes, complicating acute illness management.
Post-Infection Glucose Monitoring and Follow-Up
Given the metabolic impact of COVID-19, careful monitoring of glucose levels is an important part of post-infection care. Individuals who experienced severe illness or required corticosteroids should have their metabolic health assessed in the following months. A simple blood test, such as the HbA1c test, is recommended for follow-up screening.
All recovered patients should be aware of common symptoms of high blood sugar, including unexplained weight loss, excessive thirst, and frequent urination. If these symptoms appear, prompt medical consultation is necessary to screen for a new diabetes diagnosis. Early detection and management are key to preventing complications. Discussing metabolic health and the need for ongoing surveillance with a primary care provider is prudent for any individual recovering from COVID-19.