COVID-19 in patients with diabetes: Real-world data on factors influencing outcome

Background: Emerging data have shown associations between patients with diabetes (PwD) having excess mortality from COVID-19, but granularity is lacking. Methods: We performed a retrospective audit comparing outcomes of COVID-19 in inpatients with and without diabetes, admitted between 31 January and 23 May 2020. Demographic data (age, sex, BMI, ethnicity and postcode), co-morbidities and outcome (ITU admission, respiratory support required, 28-day mortality) were extracted from electronic patient records. For PwD, type and duration of diabetes, HbA1c, diabetes treatment, diabetes-related complications, admission glucose and ketones and episodes of hypoglycaemia (<4.0 mmol/L) or hyperglycaemia (≥12 mmol/L) were also recorded. Results: 405 patients (≥18 years) were analysed, including 108 PwD (2 with type 1 diabetes, 2 with secondary diabetes and 104 with type 2 diabetes). Three patients were newly diagnosed during admission. No patients had diabetic ketoacidosis or hyperglycaemic hyperosmolar syndrome. Median BMI was significantly higher and Index of Multiple Deprivation scores were lower in PwD. Diabetes was associated with higher 28-day mortality and need for non-invasive ventilation but not intubation or ITU admission. HbA1c, diabetes duration, admission glucose and inpatient glycaemic control did not influence ITU admission or mortality. Chronic kidney disease in PwD was associated with higher mortality (50% vs 25.8%, p=0.010). Interestingly, PwD taking metformin had significantly lower mortality (22.4% vs 45.8%, p=0.012) compared with those not on metformin. Conclusions: Our data add insight into associations between diabetes and COVID-19. Although sample size was limited, optimising weight and renal function as well as considering metformin in PwD could potentially be helpful in mitigating COVID-19 related mortality.