People living with Diabetes Mellitus and Intermediate Hyperglycaemia: risk of infections, and effects of average level and variability of glycated haemoglobin (HbA1c) on this risk, in people of different ethnic groups

Most people living with diabetes (PLWD) and their doctors worry about developing conditions like heart attacks, strokes, or eye and kidney damage. Improvements in diabetes care by keeping blood sugar levels lower, and using drugs to help prevent heart attacks and strokes (like statins, aspirin, and blood pressure lowering drugs) are reducing these problems. However, PLWD are more likely to get infections, especially bacterial and fungal infections. Some studies suggest that PLWD might be getting more serious infections than previously. COVID-19 has recently focused attention on infection in PLWD and highlighted that people from ethnic minorities are more likely to get severely ill and die. Although there are many explanations for this, for some people this is linked to their diabetes, which is more common in people from some ethnic groups. We will use UK data collected by GPs, data from hospitals and national statistics (death data). Our research team has already worked extensively on diabetes and infections using similar data, however we previously focused mainly on type 2 diabetes. We found that overall, PLWD were about 2-3 times more likely to be treated in hospital for many potentially serious infections, such as skin, bone and joint, respiratory and urinary tract infections, and sepsis (blood poisoning). While we observed potentially higher risks for people with type 1 diabetes, this only included patients aged 40 and over, so we could not provide a comprehensive picture. Our previous work was also unable to consider risks by different ethnic groups, but recent data recording improvements now make this possible. For people with type 2 diabetes, both high longer-term blood sugar levels (HbA1c) and changes in HbA1c levels over time were found to increase the chances of getting serious infections. We are now planning to examine the links between living with diabetes, high HbA1c, and changes over time in HbA1c, and infection risk for all PLWD and in different ethnic groups. Diabetes UK have identified this as a priority research area. We have started involving PLWD and we will develop this involvement further including a patient advisory group to inform the project throughout its timeline and help with dissemination. Our work has important clinical implications; we previously showed that less stable levels of blood sugars may be more important than higher sugar levels in increasing risks of infections and other complications and premature death in people with type 2 diabetes, yet targets for control focus most on HbA1c levels, not on reducing instability. Our work could also help development of future interventions specifically to reduce infections in PLWD. Finally, better knowledge of infection risks and their links with diabetes and ethnicity would inform the response to any future waves of COVID-19 and similar pandemics.