P26 - Real-Life CGM clinical analysis of glucose readings in patients transitioning from insulin glargine to insulin degludec

Background/Introduction Malta has a high incidence of Type 1 Diabetes (T1DM), likely due to genetic homogeneity and environmental factors. Insulin glargine and degludec offer more stable pharmacokinetic profiles than first-generation analogues. However, studies comparing them show mixed results regarding glycaemic control and within-day variability, though degludec is often associated with fewer hypoglycaemic events. Continuous glucose monitoring (CGM) is increasingly used to improve glycaemic management in T1DM. Purpose To evaluate glycaemic variability across different glucose ranges in patients with T1DM who transitioned from insulin glargine to insulin degludec, using CGM data. Methods A clinical audit was performed on 29 T1DM patients transitioning from insulin glargine to insulin degludec. CGM data was collected for 3 months preceding the switch, and for 3 months following a 1-month transition period. Glycaemic variability was evaluated using F-tests to compare glucose reading variances across three ranges: hypoglycaemic (<3.8 mmol/L), target (3.9–10 mmol/L), and hyperglycaemic (>10 mmol/L). No patients were directly involved in this audit. Results Glargine and degludec showed similar mean glucose levels but differed significantly in glycaemic variability. In the hypoglycaemic range, glargine showed higher variance than degludec (F = 1.048, p = 0.00014). In the target range glargine showed slightly but significantly higher variability (F = 1.007, p = 0.0114). Conversely, in the hyperglycaemic range, degludec demonstrated markedly higher variance than glargine (F = 0.671, p < 0.0001). This suggests that glargine may lead to greater glycaemic fluctuation during hypoglycaemia and normoglycaemia, while degludec may be more variable during hyperglycaemia. Mean glucose values were similar for glargine and degludec across all ranges. However, significant differences in variability were observed. This may suggest more events of hypoglycaemia with glargine than degludec. Conclusion(s) This audit detected distinct patterns of glycaemic variability between insulin glargine and insulin degludec across different glucose ranges, despite similar mean glucose levels. Glargine was associated with greater variability in the low and target glucose ranges, while degludec exhibited increased variability during hyperglycaemia. These findings may help inform optimal basal insulin choice in clinical practice. However, the small sample size restricts broader applicability, highlighting that further research with larger cohorts is warranted.