Objective This study aimed to compare clinical and sociodemographic risk factors for
severe Covid-19, influenza, and pneumonia, in people with diabetes.
Design Population-based cohort study.
Setting UK primary care records (Clinical Practice Research Datalink) linked to mortality and
hospital records.
Participants Individuals ...
Objective This study aimed to compare clinical and sociodemographic risk factors for
severe Covid-19, influenza, and pneumonia, in people with diabetes.
Design Population-based cohort study.
Setting UK primary care records (Clinical Practice Research Datalink) linked to mortality and
hospital records.
Participants Individuals with type 1 and type 2 diabetes (Covid-19 cohort: N=43,033 type 1
diabetes and N=584,854 type 2 diabetes, influenza and pneumonia cohort: N=42,488 type 1
diabetes and N=585,289 type 2 diabetes).
Primary and secondary outcome measures Covid-19 hospitalisation from 1st February
2020-31st October 2020 (pre-Covid-19 vaccination roll-out), and influenza and pneumonia
hospitalisation from 1st September 2016-31st May 2019 (pre-Covid-19 pandemic).
Secondary outcomes were Covid-19 and pneumonia mortality. Associations between clinical
and sociodemographic risk factors and each outcome were assessed using multivariable
Cox proportional hazards models. In people with type 2 diabetes, we explored modifying
effects of HbA1c and BMI by age, sex, and ethnicity.
Results In type 2 diabetes, poor glycaemic control and severe obesity were consistently
associated with increased risk of hospitalisation for Covid-19, influenza, and pneumonia. The
highest HbA1c and BMI-associated relative risks were observed in people under 70 years.
Sociodemographic-associated risk differed markedly by respiratory infection, particularly for
ethnicity. Compared to people of white ethnicity, black and south Asian groups had a greater
risk of Covid-19 hospitalisation, but a lesser risk of pneumonia hospitalisation. Risk factor
associations for type 1 diabetes and for type 2 diabetes mortality, were broadly consistent
with the primary analysis.
Conclusions Clinical risk factors of high HbA1c and severe obesity are consistently
associated with severe outcomes from Covid-19, influenza, and pneumonia, especially in
younger people. In contrast, associations with sociodemographic risk factors differed by type
of respiratory infection. This emphasises that risk stratification should be specific to
individual respiratory infections.
