Low-Dose Empagliflozin as Adjunct to Hybrid Closed-Loop Insulin Therapy in Adults With Suboptimally Controlled Type 1 Diabetes: A Randomized Crossover Controlled Trial

OBJECTIVE To assess whether low doses of empagliflozin as adjunct to hybrid closed-loop therapy improve glycemia compared with placebo in adults with type 1 diabetes (T1D) who are not able to achieve targets with the system alone. RESEARCH DESIGN AND METHODS A double-blind crossover randomized controlled trial was performed in adults with suboptimally controlled T1D (HbA(1c) 7.0-10.5%) who were not able to achieve a target time in range (3.9-10.0 mmol/L) >= 70% after 14 days of hybrid closed-loop therapy. Three 14-day interventions were performed with placebo, 2.5 mg empagliflozin, or 5 mg empagliflozin as adjunct to the McGill artificial pancreas. Participants were assigned at a 1:1:1:1:1:1 ratio with blocked randomization. The primary outcome was time in range (3.9-10.0 mmol/L). Analysis was by intention to treat, and a P value <0.05 was regarded as significant. RESULTS A total of 24 participants completed the study (50% male; age 33 +/- 14 years; HbA(1c) 8.1 +/- 0.5%). The time in range was 59.0 +/- 9.0% for placebo, 71.6 +/- 9.7% for 2.5 mg empagliflozin, and 70.2 +/- 8.0% for 5 mg empagliflozin (P < 0.0001 between 2.5 mg empagliflozin and placebo and between 5 mg empagliflozin and placebo). Mean daily capillary ketone levels were not different between arms. There were no serious adverse events or cases of diabetic ketoacidosis or severe hypoglycemia in any intervention. CONCLUSIONS Empagliflozin at 2.5 and 5 mg increased time in range during hybrid closed-loop therapy by 11-13 percentage points compared with placebo in those who otherwise were unable to attain glycemic targets. Future studies are required to assess long-term efficacy and safety.