The researchers published the study covered in this summary on medRxiv.org as a preprint that has not yet been peer reviewed.

Key points to remember

  • Results of a retrospective, observational, case-control study of over 20,000 people from a single US medical center showed a statistically significant but clinically insignificant increase in A1c in people following COVID-19 infection , in those with and without diabetes.

  • After people were diagnosed with COVID-19 infection, they were 40% more likely to also be diagnosed with type 2 diabetes compared to people who tested negative for COVID-19, a difference significant, which could be explained by the increase in medical care. received by people who test positive for COVID-19.

  • The risk of incident diabetic ketoacidosis (DKA) in people who tested positive for COVID-19 was significantly higher in people with pre-existing type 2 diabetes, those using insulin and in black people.

why it matters

  • The authors said their study is the first report of evidence that COVID-19 infection affects A1c levels in a large, real-world clinical cohort.

  • Until now, the impact of COVID-19 infection on A1c remained unclear. Results from previous studies have indicated that COVID-19 infection can raise A1c levels, but the cohorts studied were small and lacked uninfected controls.

  • The current study included 8,755 people infected with COVID-19, had pre- and post-infection data on diabetes status and A1c levels, and also included many matched, uninfected people who served as controls. .

study design

  • The data comes from a Cleveland Clinic registry that included 81,093 people who tested positive for COVID-19 between March 2020 and May 2021 and 153,034 matched people who tested negative for COVID-19 during the same period.

  • The researchers retrospectively selected patients with an A1c recorded within 12 months before their COVID-19 test as well as a second A1c value recorded within 12 months after the COVID-19 test. This produced a study cohort of 8,755 COVID-positive people and 11,998 matched people who tested negative for COVID-19.

  • To assess the risk of DKA onset after COVID-19 infection, the authors identified two subcohorts that excluded people with a history of DKA. The subcohorts were made up of 701 people with type 1 diabetes and 21,830 people with type 2 diabetes.

Principle results

  • The investigators found a statistically significant but clinically insignificant increase in A1c following a positive COVID-19 test, an average increase in A1c of 0.06 percentage points. Those who tested negative for COVID-19 had a clinically insignificant change in their mean A1c level that was borderline statistically significant, an average increase of 0.02 percentage points, P = 0.05

  • The statistically significant but clinically insignificant increase in A1c after COVID-19 infection was similar in people with and without type 2 diabetes before infection.

  • In patients with type 2 diabetes who were infected with COVID-19, researchers found significant positive associations between higher A1c levels before infection and time to hospitalization (relative risk, 1 .07), need for respiratory support (HR, 1.06) and admission to intensive care. (HR, 1.07).

  • Following COVID-19 infection, people were 40% more likely to be diagnosed with incident type 2 diabetes compared to matched uninfected people. The authors said one possible explanation is that after diagnosis of COVID-19, infected people in general received more intensive care which led to better identification of people with underlying type 2 diabetes.

  • The 701 people included with pre-existing type 1 diabetes showed no significant difference in their rate of developing ACD between people infected and uninfected with COVID-19.

  • Among the 21,830 people with pre-existing type 2 diabetes, the risk of DKA was significantly higher by 35% for those who were infected with COVID-19 compared to those who were not infected. The magnitude of this increased relative risk was even greater in patients with type 2 diabetes who used insulin as part of their treatment.

  • The difference in DKA risk did not differ between black and white patients who were not infected with COVID-19, but among those infected with COVID-19, black patients were more than twice as likely to receive a diagnosis of ACD than white patients, a significant difference.

  • Black patients with type 2 diabetes who were infected with COVID-19 had a significant 63% increase in ACD rate compared to black patients with type 2 diabetes who were not infected.

Limits

  • The study included patients with A1c measurements taken up to 12 months prior to their COVID-19 test, and therefore comorbid conditions, medication changes during this time, or other factors that may have affected the subsequent A1c levels. To address this issue, the authors also assessed results at 3- and 6-month intervals, which produced results consistent with the 12-month results.

  • Researchers did not have A1c values ​​for many of the more than 234,000 people across the registry who underwent COVID-19 testing from March 2020 to May 2021 at the Cleveland Clinic, omissions that may have biased the study cohort.

  • This was a single center study. Some patients may have received care outside of the center and therefore records for these episodes could not be included.

Disclosures

  • The study received no commercial funding.

  • Four authors have received consultant and speaker fees and research funding from AstraZeneca, Bayer, Boehringer Ingelheim, Corcept Therapeutics, Diasome, Eli Lilly, Merck, Novo Nordisk and Sanofi.

  • Three authors hold intellectual property related to therapeutic decision-making in the context of type 2 diabetes.

This is a summary of a pre-publication research study “Impacts of COVID-19 on Blood Glucose and Risk of Diabetic Ketoacidosis,” written by Cleveland Clinic researchers on medRxiv, provided by Medscape. The study has not yet been peer reviewed. The full text of the study is available at medRxiv.org.

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