39-LB: A Comparison of Insulin Glargine U300 and Insulin Degludec around Spontaneous Exercise Sessions in People with Type 1 Diabetes—The ULTRAFLEXI-1 Study

Background and aims: Regular physical activity and exercise represent a corner stone in the treatment of type 1 diabetes (T1D) , however, exercise-induced hypoglycemia remains the major barrier to a physically active lifestyle. Therefore, the ULTRAFLEXI-1 study compared two basal insulin analogues, Glargine 300U/ml (IGlar U300) and Degludec (IDeg) , in two different doses (100% and 75% of the regular dose) when used around spontaneous exercise sessions in adults with T1D.

Methods: We performed a randomized, single-center, four-period, cross-over trial (EudraCT: 2019-003209-89) and included adults with T1D treated with multiple daily insulin injections and an HbA_1c ≤10% (≤86 mmol/mol) . In each of the four 2-weeks-periods, participants attended six spontaneous evening cycling sessions (60 minutes, moderate intensity) . The days of exercising were randomized and announced at 8 A.M. to the participants. The basal insulin used on the exercise days during the four periods were: IGlar U300 100% or 75% of the regular dose or IDeg 100% or 75%, respectively. 100% of the regular basal insulin dose was used at all non-exercise days. CGM was performed using a blinded Dexcom G6 device. The primary outcome was TBR (<70 mg/dl) during the six 24-hour post-exercise periods in the four trial arms. The difference in TBR between 100% IGlar and 100% IDeg or 75% IGlar and 75% IDeg was analyzed in hierarchical order using the repeated measures linear mixed model.

Results: 25 people were enrolled (14 male) , aged 41.4±11.9 years, with a mean diabetes duration of 16.8±10.4 years and a mean HbA_1c of 7.5±0.8%. (59±9 mmol/mol) . Mean TBR during the 24-hour periods following the exercise sessions was 2.71±2.56% for IGlar U300 (100%) and 4.37%±3.43% for IDeg (100%) (p=0.025) as well as 2.28±2.67% for IGlar U300 compared to 2.55 ±2.87% with IDeg when using the 75% dose on exercise days (p=0.720) .

Conclusion: Time spent in hypoglycemia after spontaneous exercise sessions was significantly lower in people with type 1 diabetes receiving IGlar U300 as compared to IDeg when the 100% dose was used.