Type 1, type 2 diabetes linked to elevated COVID-19 mortality risk
medwireNews: Both type 1 and type 2 diabetes are independently associated with an increased risk for death among hospitalized patients with COVID-19, and a number of factors including poor glycemic control and BMI may predict mortality risk, suggest findings from two studies published in The Lancet Diabetes & Endocrinology.
In the first, Jonathan Valabhji (NHS England and NHS Improvement, London, UK) and co-researchers conducted a whole-population study of all 61,414,470 people in England who were alive and registered with a primary care practice in February 2020, of whom 0.4% had a recorded diagnosis of type 1 diabetes, and 4.7% of type 2 diabetes.
Of 23,698 people who died in hospital with COVID-19 between 1 March and 11 May 2020, approximately a third had diabetes, including 1.5% with type 1 diabetes and 31.4% with type 2 diabetes. These results translated into unadjusted mortality rates per 100,000 people of 138 for type 1 diabetes and 260 for type 2 diabetes, compared with just 27 for people without diabetes.
The researchers note that the higher unadjusted mortality rates among people with type 2 compared with type 1 diabetes “largely reflect[ed] the different age structure of the two populations,” with type 2 diabetes patients mainly falling into age categories of 60 years or older and patients with type 1 diabetes predominantly representing younger age categories.
In a multivariable analysis accounting for age, sex, deprivation, ethnicity, and geographic region, people with type 1 diabetes had a significant 3.51-fold increased risk for COVID-19 mortality relative to people without diabetes, while patients with type 2 diabetes had a significant 2.03-fold increased risk. These increased risks remained significant but were attenuated to 2.86- and 1.80-fold, respectively, after additional adjustment for cardiovascular comorbidities.
Together, these findings show that “[p]eople with diabetes are at higher risk of COVID-19-related mortality than people without diabetes,” say the researchers, but they stress that “mortality risk was very low for people younger than 40 years with either type 1 or type 2 diabetes.”
In the second study, Valabhji and team used data from the English National Diabetes Audit linked to death records from 2 January to 11 May 2020 to evaluate risk factors associated with COVID-19 mortality among people with type 1 and type 2 diabetes.
They found that of 1604 people with type 1 diabetes who died during this period, 28.9% had COVID-19 included on the death certificate, as did 29.0% of 36,291 individuals with type 2 diabetes.
After adjustment for potentially confounding factors, the researchers identified a number of nonmodifiable risk factors for COVID-19 mortality including older age, male sex, renal impairment, non-White ethnicity, socioeconomic deprivation, and previous cardiovascular disease.
However, they also found that higher glycated hemoglobin (HbA1c) levels were associated with increased COVID-19 mortality risk, with a significant hazard ratio (HR) of 2.23 for type 1 diabetes and 1.61 for type 2 diabetes when comparing HbA1c levels of 86 mmol/mol (10.0%) or higher versus 48–53 mmol/mol (6.5–7.0%).
There was a U-shaped relationship between BMI and COVID-19 mortality risk. Among people with type 1 diabetes, those with a BMI of less than 20.0, 20.0–24.9, 30.0–34.9, 35.0–39.9, or 40 kg/m² or higher had a significantly higher risk than those with a BMI of 25.0–29.9 kg/m². A similar pattern of results was seen for type 2 diabetes, but mortality risk was comparable in the 25.0–29.9 and 30.0–34.9 kg/m² categories.
“Although several risk factors identified for COVID-19-related mortality in people with diabetes cannot readily be modified, HbA1c can be improved by health-care interventions,” write the researchers.
They add that “[a]lthough the association with obesity was more complex, particularly in the type 2 diabetes population, bodyweight can also be affected by health-care interventions—a goal of routine care.”
And the team concludes: “Improved achievement of standard diabetes care recommendations that target prevention of cardiovascular and microvascular complications might also serve to beneficially modify some of the risk factors that we have shown to be associated with COVID-19-related mortality.”
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2020 Springer Healthcare Ltd, part of the Springer Nature Group
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