High body mass index (BMI), poor renal function, and microvascular complications were found to be associated with a greater risk of death or intensive care unit (ICU) admission for people with type 1 diabetes and COVID-19, according to research results published in Diabetologia.

Population-based studies in the United Kingdom reported that by May 2020, 1.5% of all 23,698 in-hospital COVID-19-related deaths occurred in people with type 1 diabetes, while people with type 2 diabetes accounted for 31.4% of these deaths. Additional research has demonstrated further relationships among hyperglycemia, newly diagnosed diabetes, fasting plasma glucose levels, and COVID-19 mortality, but studies have been small.

In the current retrospective cohort study, researchers sought to describe the characteristics of people in the United Kingdom with type 1 diabetes who were admitted to the hospital with COVID-19, while also identifying the risk factors that might be associated with severe disease. Data were collected from a nationwide audit by the Association of British Clinical Diabetologists (ABCD) beginning in September 2020. Information on demographics, clinical characteristics, medication history, and laboratory values, among other data, were collected.

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Through December 2020, 40 National Health Service centers in the United Kingdom submitted data to the national audit, for a final dataset containing 3312 patient records; of those, 196 were for patients with type 1 diabetes hospitalized from March to October 2020. All of these patients were receiving insulin therapy.

The patient cohort was 55% men and 70% White, with a mean age of 62 years (±19 y) and a BMI of 28.3 kg/m2 (±7.3 kg/m2). Mean glycated hemoglobin (HbA1c) was 9.1% (±5.0%). Among 50% of the patients, the latest available HbA1c was less than 7.5%.

Both diabetic retinopathy (45%) and hypertension (58%) were common. Approximately half (56%) of the patients had microvascular complications including diabetic nephropathy, foot ulcers, retinopathy, or peripheral neuropathy; 39% had a macrovascular complication, including peripheral vascular disease, ischemic heart disease, or cerebrovascular disease.

Overall, 27% of the study population died from COVID-19, with most deaths occurring among patients aged 55 to 74 years and those aged 75 years and older (38% in each group). Both serum creatinine and macrovascular disease were positively associated with mortality rate after adjusting for age.

Median time between admission and in-hospital death was 7 days (interquartile range, 4-15). Thirty of these deaths occurred within 1 week of admission, while 2 occurred after 7 weeks. In total, 35% of the patients died or were admitted to the adult ICU.

Results of a logistic regression analysis showed that BMI, serum creatinine, and the presence of microvascular disease were all positively associated with the study’s primary outcome, following adjustment for age; conversely, higher admission blood glucose levels were negatively associated with this primary outcome. However, the researchers noted that there was a statistically significant difference in mean blood glucose values between those with and without diabetic ketoacidosis, which was “likely to account for this unexpected finding.”

Study limitations included those inherent to retrospective analyses, as well as the lack of data from “contemporaneous hospital admissions” of those with type 1 diabetes without COVID-19 infection, as well as from those with type 1 diabetes and COVID-19 who were not admitted to the hospital. Results are not generalizable to those outside of this subgroup of patients.

“We report the largest study of people with type 1 diabetes admitted to the hospital with COVID-19,” the researchers wrote. “In this population, higher BMI, worse renal function, and the presence of microvascular complications were associated with higher risk of death and/or admission to [adult] ICU. Risk of severe COVID-19 is reassuringly very low in people with type 1 diabetes who are under 55 years of age without microvascular or macrovascular disease,” they concluded. 

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Ruan Y, Ryder REJ, De P, et al; ABDC Covid-19 Audit Group. A UK nationwide study of people with type 1 diabetes admitted to hospital with COVID-19 infection. Diabetologia. Published online May 8, 2021. doi:10/1007/s00125-021-05463-x