Study: New-Onset Diabetes and COVID-19: Evidence from a Global Clinical Registry. Image Credit: ADragan / Shutterstock

Study suggests that COVID-19 may cause diabetes

The authors of a new study that is reviewed at Nature portfolio and currently posted on Research Square preprint* server showed the clinical possibility that coronavirus disease 2019 (COVID-19) increases the risk of developing diabetes mellitus (DM), supports diabetes screening in persons infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Study: New-onset diabetes and COVID-19: Evidence from a global clinical registry. Image credit: ADragan / Shutterstock


A growing body of evidence suggests that COVID-19 is associated with new diabetes diagnoses. However, it is unclear whether COVID-19 detects pre-existing diabetes or induces new-onset diabetes.

Although previous research has reported high blood sugar levels and metabolic consequences of pre-existing diabetes after hospitalization with COVID-19, there are few studies correlating this disease with new-onset DM.

COVID-19 has been shown to worsen pre-existing diabetes. This likely occurs because COVID-19 is associated with low-grade inflammation that can initiate or exacerbate insulin resistance. In addition, numerous studies have also shown that SARS-CoV-2 can infect and multiply in insulin-producing pancreatic beta-cells, thereby disrupting insulin synthesis and secretion.

However, whether SARS-CoV-2 can cause clinically significant changes in glucose metabolism remains unclear. Nevertheless, it may be possible to find an answer by characterizing the clinical signs of diabetes associated with COVID-19 and determining the period between the onset of hyperglycemia and the onset of infection.

It is imperative to establish a causal link between COVID-19 and diabetes, as both diseases are prevalent worldwide. Furthermore, establishing a causal relationship will have significant implications for diagnosis, management, public health, and scientific research. Despite this, it remains unclear whether the link between COVID-19 and diabetes results from the indirect health consequences of the former, such as – a higher rate of capture of pre-existing diseases, or whether the virus (SARS-CoV-2) directly accelerates hyperglycemia.

Given the higher detection rate of pre-existing conditions in the COVID era, newly diagnosed diabetes can be explained both during and after an episode of infectious exposure.

Study; studies

This study investigated the possibility that COVID-19 may trigger new-onset diabetes and associated symptoms by examining mean blood glucose levels at the time of diabetes onset based on a global clinical registry.

The Global Registry of COVID-19-Associated Diabetes (CoviDIAB) was established to determine whether COVID-19 can acutely induce diabetes and its clinical symptoms. The CoviDIAB registry collects information related to “newly diagnosed diabetes” and “severe metabolic complications associated with pre-existing diabetes” resulting from COVID-19.

Individuals with a fasting blood glucose of 126 mg/dL or greater or a fasting blood glucose of 200 mg/dL or greater, with no previous history of diabetes and those who have never used glucose-lowering drugs, and with their glycated hemoglobin (HbA1c) levels below the diabetes range (< 6, 5%) were categorized as new-onset diabetes at presentation. Here, researchers examined cases of newly diagnosed diabetes that occurred within four weeks of being confirmed with COVID-19. In addition, HbA1c data were assessed at the time of diabetes detection to rule out pre-existing hyperglycemia and to confirm an association with SARS-CoV-2 infection.


Data on 537 eligible newly diagnosed diabetes cases were entered from 61 hospitals in 25 countries in 2020-2022. COVID-19 patients with newly diagnosed diabetes at presentation had HbA1c levels above the diagnostic range, suggesting pre-existing hyperglycemia.

In cases with new-onset hyperglycemia after SARS-CoV-2 infection, individuals showed glycemic levels above diagnostic thresholds, although their HbA1c levels remained in the non-diabetic range. Results showed that 22% of newly diagnosed patients with documented HbA1c levels had recently acquired diabetes.

The most common subtype of diabetes in adults was type 2 DM (59%) and the “not yet known” subtype (41%). Among children, two newly diagnosed cases of type 1 DM were recorded. After resolution of COVID-19, hyperglycemia persisted in 39 of 89 patients (45%) with newly diagnosed diabetes.

For 28 of these individuals, follow-up data of more than three months were collected, showing that five of them were in remission from diabetes, while 23 (82%) remained diabetic.

The findings suggest that COVID-19 causes clinically significant changes in glucose metabolism. Although this study does not prove that SARS-CoV-2 causes diabetes, it strongly suggests that the virus may cause diabetogenic consequences.

Furthermore, type 2 DM was the predominant subtype among COVID-19 participants with newly diagnosed diabetes. Thus, type 2 DM probably accounts for the majority of newly diagnosed diabetes cases associated with the post-acute phase of SARS-CoV-2 infection.

This study confirms this phenomenon across different geographic locations and ethnicities by incorporating clinical observations from 25 countries.

Many areas for improvement were identified in this study, including the inherent heterogeneity in clinical practice and the judgment of contributing physicians.


The results of this study suggest that COVID-19 is likely to have a diabetogenic effect. Individuals exposed to SARS-CoV-2 infection must therefore be screened for diabetes. Further research is needed to confirm the mechanisms by which the virus interferes with glucose metabolism.

*Important notice

Research Square publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guiding clinical practice/health-related behavior, nor should they be treated as verified information.

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