Introduction: Real-world evidence on the effectiveness and safety of insulin degludec (IDeg) in patients with diabetes is a priority. We have therefore evaluated the effectiveness and safety of IDeg, including impact on metabolic control, glycemic variability, weight gain and hypoglycemia, in patients with type 1 diabetes under routine clinical practice conditions. Methods: This was an observational longitudinal multicenter study. A retrospective chart review of Enhanced Digital Features To view enhanced digital features for this article go to https://doi.org/10.6084/ m9.figshare.10042994.