To Örebro University

Introduction: Hypoglycaemia is a common side effect of insulin therapy; low or high glycated haemoglobin (HbA(1c)) levels, history of hypoglycaemia or long diabetes duration are known modifiers of hypoglycaemia risk. In randomised clinical trials, lower rates of hypoglycaemia have been observed with the new-generation insulin analogue, long-acting insulin degludec, compared with other basal insulins.

Methods: The ReFLeCT study was a prospective observational study over 12 months. Patient-reported diary data on hypoglycaemia were collected from patients with type 1 diabetes (T1D) or type 2 diabetes (T2D) who were switching from other basal insulins to insulin degludec (degludec) at their physician's discretion in routine clinical care. Two secondary analyses were undertaken to investigate the change in number of hypoglycaemic events: a post hoc analysis using the updated American Diabetes Association (ADA) level 1, 2 and 3 hypoglycaemia definitions, and a pre-specified analysis using patient characteristics (baseline HbA(1c), diabetes duration, and physician's rationale for initiating degludec).

Results: Switching to degludec was associated with significantly fewer hypoglycaemic events for all definitions in T1D, and level 1 and 2 in T2D (too few level 3 events for statistical comparison). Moreover, patient characteristics did not influence the observed reduction in hypoglycaemia in T1D and T2D.

Conclusion: These results demonstrate that switching to degludec from other basal insulins was associated with reduced rates of hypoglycaemia, irrespective of the definition used or baseline patient characteristics.

Plain Language Summary: Low blood sugar levels (hypoglycaemia) are a common, and sometimes serious, side effect of treatment with insulin in people with diabetes. In the ReFleCT study, adults with type 1 (T1D) and type 2 diabetes (T2D) were asked to complete a diary for 12 months when their doctor changed their previous long-acting insulin treatment to insulin degludec (degludec). The key outcome of the study was whether the frequency of hypoglycaemia changed when a patient's insulin treatment was switched. Here, we used the diary information from the ReFLeCT study to investigate whether the change in the rate of hypoglycaemia was related to the way hypoglycaemia was defined, or to patients' characteristics at the time their insulin was switched. These characteristics included the length of time that patients had had diabetes, their blood sugar control, and their doctor's reason for changing their medication. Our findings showed that the way hypoglycaemia was defined, and patients' characteristics, did not generally influence the frequency of hypoglycaemia for patients with T1D or T2D. However, the most severe hypoglycaemia in patients with T2D occurred too infrequently to be assessed. Patients in all groups had less hypoglycaemia overall after switching compared with their previous treatment, suggesting that degludec may be a treatment option for a broad range of patients with diabetes.