Association of severe hypoglycemia with mortality for people with diabetes mellitus during a 20-year follow-up in Denmark: a cohort study

Aims Severe hypoglycemia has a significant deteriorating effect on quality of life of the individual and has been associated with increased mortality. The aim of this study was to investigate the mortality among people with type 1 and type 2 diabetes suffering from severe hypoglycemia in Denmark in the last two decades. Methods People diagnosed with type 1 ( n = 44,033) and type 2 diabetes ( n = 333,581) were extracted from the complete population of Denmark from 1996 to 2017 via ICD-10 diabetes codes and ATC diabetes medication codes. People suffering from severe hypoglycemia (type 1 diabetes n = 8808, type 2 diabetes n = 5605) as identified from ICD-10 codes were then matched 1:1 by year of birth, gender and year of diabetes diagnosis with those without severe hypoglycemia. Cox proportional hazards models were constructed to analyze the effect of severe hypoglycemia on mortality. Results For both people with type 1 (HR 1.11, CI 95% 1.06 to 1.17) and type 2 diabetes (HR 1.77, CI 95% 1.67 to 1.87) suffering from hypoglycemia, an increased mortality risk was observed, compared to people without severe hypoglycemia. An investigation of the death causes did not indicate an association between the severe hypoglycemic episodes and death. Conclusion In this study, severe hypoglycemic episodes increased the mortality risk for people with type 1 and type 2 diabetes. The risk was higher among people with type 2 diabetes. Whether severe hypoglycemia is a symptom of other underlying illnesses increasing mortality risk or a risk factor itself needs further investigation.