Switching to Degludec From Other Basal Insulins Is Associated With Reduced Hypoglycemia Rates

A Prospective Study

Gian Paolo Fadini; Michael Feher; Troels Krarup Hansen; Harold W. de Valk; Mette Marie Koefoed; Michael Wolden; Esther Zimmermann; Johan Jendle


J Clin Endocrinol Metab. 2019;104(12):5977-5990. 

In This Article

Abstract and Introduction


Context: Observational studies of insulin degludec (degludec) with hypoglycemia events prospectively recorded are lacking.

Objective: To evaluate the safety and effectiveness of degludec in patients with type 1 diabetes (T1D) or type 2 diabetes (T2D) switching from other basal insulins in routine care.

Design: Results From Real-World Clinical Treatment With Tresiba® was a multinational, multicenter, prospective, observational, single-arm study comprising a 4-week baseline period (preswitch basal insulin) and 12-month follow-up (degludec).

Setting: Routine clinical practice.

Patients or Other Participants: Insulin-treated patients (≥18 years) with T1D (n = 556) or T2D (n = 611) with treatment plans to initiate degludec.

Interventions: Switching to degludec from other basal insulins.

Main Outcome Measure: Change from baseline in number of overall hypoglycemic events recorded in patient diaries.

Results: In T1D, the 12-month follow-up/baseline rate ratios (95% CI) of overall [0.80 (0.74 to 0.88)], nonsevere [0.83 (0.76 to 0.91)], severe [0.28 (0.14 to 0.56)], and nocturnal [0.61 (0.50 to 0.73)] hypoglycemia suggested significantly lower hypoglycemia rates with degludec (all Ps < 0.001). At 12 months, HbA1c, fasting plasma glucose (FPG), and basal insulin dosage decreased significantly. Body weight increased, and treatment satisfaction improved significantly. In T2D, the hypoglycemia rate ratios were overall [0.46 (0.38 to 0.56)], nonsevere [0.53 (0.44 to 0.64)], and nocturnal [0.35 (0.20 to 0.62)] (all Ps <0.001; too few events for analysis of severe hypoglycemia). At 12 months, HbA1c and FPG decreased significantly. Body weight and insulin dosages remained unchanged, and treatment satisfaction was significantly improved.

Conclusions: In a routine clinical care setting, switching to degludec from other basal insulins was associated with significantly lower rates of hypoglycemia, improved glycemic control, and treatment satisfaction in patients with T1D or T2D.


Hypoglycemia is a common treatment-related event among patients with type 1 diabetes (T1D) or type 2 diabetes (T2D) treated with insulin and is often a key barrier to obtaining good glycemic control.[1,2] Additionally, hypoglycemia may adversely affect physical, mental, and social functioning, compromises work and leisure activities, and may lead to delays in treatment intensification.[3–7] Therefore, reducing the risk of insulin-induced hypoglycemic events is essential in the management of diabetes.

Insulin degludec (degludec) is a basal insulin analog with an ultralong duration of action >42 hours at steady state and a lower day-to-day variability in blood glucose (BG)-lowering effect compared with insulin glargine 100 U/mL (glargine U100)[8,9] and 300 U/mL (glargine U300).[10] In addition, treat-to-target, randomized controlled trials (RCTs) have demonstrated that degludec is associated with a reduced risk of hypoglycemia compared with other basal insulin analogs, at equivalent glycemic control, for patients with either T1D or T2D.[11–15]

RCTs are considered the gold standard in providing evidence of drug efficacy and safety under controlled trial conditions in a specific patient population.[16,17] However, other sources of data are necessary to establish the effectiveness and long-term safety of drug treatments in real-world clinical practice and in a broader patient population.[16,17] Therefore, the Results From Real-World Clinical Treatment With Tresiba® (ReFLeCT) study was designed to explore the safety and effectiveness of switching patients from other basal insulins to degludec over a 12-month period via a prospective study design. While ReFLeCT was ongoing, treatment with degludec was also being evaluated in other real-world studies with both retrospective and prospective study designs.[18–29] These real-world studies demonstrated that degludec was associated with improved glycemic control and reduced hypoglycemia rates compared with previous basal insulin treatment. However, none of these studies prospectively collected hypoglycemia data from patient diaries and were thus limited by the bias of patients' recollection of previous events in electronic medical records. ReFLeCT was established as an observational study that collected hypoglycemic event data prospectively by using patient diaries and evaluated patients' perspectives on treatment with degludec.

The aims of the ReFLeCT study were to evaluate the clinical safety and effectiveness of switching to degludec from other basal insulins in routine clinical care of insulin-treated adults with T1D or T2D attending multiple diabetes centers across Europe.