The Effects of Subcutaneous Insulin Infusion Versus Multiple Insulin Injections on Glucose Variability in Young Adults with Type 1 Diabetes: The 2-Year Follow-Up of the Observational METRO Study

Background: Type 1 diabetic patients have high instability of daily glucose levels. The aim of this study was to evaluate the long-term effects of continuous subcutaneous insulin infusion (CSII) therapy, compared with multiple daily injections of insulin (MDI), on glucose variability, in young type 1 diabetic patients transitioned to the adult diabetes care. Methods: Patients aged 18-30 years and considered eligible for insulin pump therapy were included in the study. Ninety-eight patients who started CSII therapy and 125 who remained in MDI completed a 2-year follow-up. Glucose variability was assessed with continuous glucose monitoring using blood glucose standard deviation (BGSD), mean amplitude of glycemic excursion (MAGE), continuous overall net glycemic action (CONGA-2h), low blood glucose index, high blood glucose index, and average daily risk range. Results: MAGE and BGSD decreased in both groups, with adjusted differences at 2 years of -0.74mM (95% confidence interval [CI] -1.22 to -0.26, P=0.003) and -0.3 (CI -0.52 to -0.1, P=0.005) favoring the pump-therapy group. No significant differences between groups in the other variability indexes were observed. HbA1c decreased in both groups without significant difference (0.05%, -0.26, 0.35, P=0.77); fasting glucose, insulin dose, and overall hypoglycemia (daily, nocturnal, and severe) decreased more in patients with CSII, compared with those with MDI. Conclusions: Among young adults with type 1 diabetes transitioning from the pediatric care, the use of CSII is associated with lower glucose variability, fasting glycemia, and overall hypoglycemic events than MDI during a 2-year period of follow-up.