Reporting Severe Hypoglycemia in Type 1 Diabetes: Facts and Pitfalls

To describe potential factors influencing reporting of severe hypoglycemia in adult patients with type 1 diabetes and to analyze their effect on reported rates of severe hypoglycemia.

Reported rates of severe hypoglycemia defined as need for third party assistance vary between 0.3-3.0 events per patient-year in unselected cohorts, corresponding to a yearly prevalence range of 10-53%. When defined as need for parenteral therapy with glucose or glucagon or need for admission to an emergency unit or hospitalization, incidence and prevalence rates of severe hypoglycemia are 0.02-0.5 events per patient-year and 1-29%, respectively. When subjects with recurrent severe hypoglycemia in the past or suffering from impaired hypoglycemia awareness are excluded from participation in studies, lower rates are reported. Studies applying anonymous reporting or reporting by partners report higher rates of severe hypoglycemia. There is a large variation between studies reporting incidence and prevalence of severe hypoglycemia in patients with type 1 diabetes, mainly explained by definition of severity, methods of reporting, and patient selection. These findings call for consensus about hypoglycemia definition and reporting in future research.