Continuous Subcutaneous Insulin Infusion in Type 1 Diabetes Mellitus Patients: Results from the Spanish National Registry.

Aim: To analyze the clinical effect of continuous subcutaneous insulin infusion (CSII) in type 1 diabetes mellitus (T1D) patients in the Spanish real-world scenario. Methods: All T1D patients on CSII registered in the SPAnish Insulin Pump (SPAIP) registry were included. The primary efficacy outcome was change in HbA1c during follow-up. Secondary efficacy outcomes included: insulin pump indications, diabetes complication rates, insulin and pump use, and continuous glucose monitoring (CGM) glycometrics. Patient data were typed through the web-based SPAIP registry. Results: Data from 2979 T1D patients treated with CSII were analyzed. The median age was 44 years (interquartile range [IQR] 34-52 years), and T1D duration was 27 years (IQR 18-35 years). The median duration of CSII therapy was 6 years (IQR 3-10 years). The main indications for treatment were suboptimal glycemic control (33.8%), hypoglycemia (22.1%), and increased glycemic variability (18.8%). Glycated hemoglobin decreased by 6 mmol/mol (95% CI, -5 to -6 mmol/mol, P  < 0.001) [-0.5%, 95% CI, -0.4 to -0.5, P  < 0.001] during the follow-up. The percentage of patients with severe hypoglycemia decreased from 14.9% to 0.9% ( P  < 0.001). We observed an inverse correlation between final HbA1c levels and CGM adherence ( R  = -0.24, P  < 0.001) or percentage of time with active hybrid closed-loop functions ( R  = -0.25, P  < 0.001). Conclusions: CSII treatment was associated with a sustained improvement in glycemic control in the Spanish population. This benefit was greater among patients with higher CGM or active hybrid closed-loop functions adherence. The protocol was publicly registered at ClinicalTrials.gov (NCT04761094).