While there is overwhelming evidence that people with diabetes tend to experience worse outcomes if they develop COVID-19 — especially if they have a history of less than optimal blood glucose control — the link between COVID-19 and new cases of diabetes is less convincing. Some research suggests that many new cases of diabetes in the wake of COVID-19 may be temporary, at least in people hospitalized with the viral infection. But other research suggests that many people develop diabetes — or at least impaired glucose tolerance — as part of a collection of long-term symptoms known as long COVID. In some people, impaired glucose tolerance or diabetes may begin months after they initially develop COVID-19 — so that the link between the two conditions is less clear than in people who develop diabetes during a hospitalization related to COVID-19.
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For the latest analysis, researchers looked at a database representing 1,171 doctor’s offices in Germany, which aims to be representative of the country at large. The researchers compared the rate of new cases of diabetes between March 2020 and July 2021 with two other diagnoses included in the database — COVID-19 and acute upper respiratory tract infections (AURI) — between March 2020 and January 2021. Out of about 8.8 million patients in the database, there were 35,865 documented cases of COVID-19 during the study period, and the researchers matched these study participants with an equal number of people who developed AURI during the same period and had similar characteristics in several areas — including age, sex, health insurance status, month in which they developed the infection, and current or past health conditions such as obesity, hypertension, heart attack, or stroke. In both the COVID-19 and AURI groups, the average age was 43, and 46% of participants were female.
COVID-19 linked to higher rates of new type 2 diabetes
The researchers found that in the COVID-19 group, the rate of new cases of type 2 diabetes was 15.8 per 1,000 person-years — while in the AURI group, it was 12.3 per 1,000 person-years. Using a complex system of modeling, the researchers calculated that compared with having an AURI, having COVID-19 was linked to a 28% higher risk for developing type 2 diabetes during the study period. No increased risk was found for other forms of diabetes.
“COVID-19 confers an increased risk for type 2 diabetes,” the researchers concluded. “If confirmed, these results support the active monitoring of glucose dysregulation after recovery from mild forms” of COVID-19 — not just in people hospitalized with the infection who experienced elevated blood glucose levels during their hospitalization.
Want to learn more about coronavirus and diabetes? Read our latest COVID-19 updates.