Continuous Glucose Monitoring to Compare Glycemic Patterns and Variability in Insulin-Treated Pancreatic Diabetes Mellitus with Type 1 Diabetes and a Clue to the Influence of Pancreatic Enzyme Replacement

Background: Pancreatic diabetes (T3cDM) is a unique form of diabetes in the young characterized by dysfunction and marked loss of beta cells and alpha cells, as well as pancreatic exocrine insufficiency and poor incretin response. While most cases of T3cDM are insulin dependent, they are prone to hyperglycemic and hypoglycemic excursions and high glycemic variability (GV). There is a scarcity of data on continuous glucose monitoring (CGM) in T3cDM. Objectives: To compare glycemic patterns and variability in T3cDM and type 1 diabetes mellitus (T1DM) and assess the role of pancreatic enzyme replacement therapy (PERT) on GV. Methods: A total of 70 patients with DM on insulin (T3cDM = 35, T1DM = 35) underwent flash CGM for 14 days. CGM metrics were compared between T1DM and T3cDM and among T1DM, T3cDM receiving PERT, and T3cDM not receiving PERT. Results: T3cDM patients had significantly lower eA1c% (7.93 vs 10.08), higher TIR (40.69 vs 27.5), lower CV (37.07 vs 43.58), and lower TAR (47.57 vs 61.44) than T1DM ( P < 0.05 for all). There were no differences in hypoglycemia indices like TBR between the groups. Compared to T1DM, higher TIR (46.55 vs 27.5) and lower CV (33.53 vs 43.58) were noticed in the T3cDM-PERT group but not in the T3cDM-no PERT group. However, postmeal hypoglycemia was also more common in T3cDM-PERT (35% vs 20% vs 6.3% for T3cDM-PERT, T3cDM-no PERT, and T1DM, respectively, P = 0.03). Conclusion: Patients with T3cDM on insulin have lower GV and hyperglycemia than T1DM, but similar hypoglycemia risk. PERT improves TIR and lowers postmeal hyperglycemic excursions but might increase postmeal hypoglycemia. However, the current study was underpowered to evaluate the role of PERT, necessitating larger studies in this field.