Endocrine Abstracts

Introduction: Many patients with diabetes experience high variability in glucose concentrations which is associated with a risk of hypoglycemia. The aim of this was to compare the predictive value of HbA1C, mean interstitial glucose (MIG), and glucose variability (GV) in the risk of hypoglycemia in patients with type 1 diabetes (T1D).

Methods: Continuous glucose monitoring, using CGMS system, was performed in 130 T1D patients with diabetes duration of 17.1±8.6 years, in intensive insulin therapy (49.8±17.9 IU). MIG (in mg/dl), GV measured by standard deviation of MIG (mg/dl), time per day spent in hypoglycemia (HT), interstitial glucose ≤70 mg/dl (h), and episodes of nocturnal hypoglycemia (NH), hypoglycemia between midnight and 0800 h, in %, were assessed. Patients were divided in group I (n=84) with HbA1c ≤7.5%, and group II (n=46) with HbA1c >7.5%. Statistical analysis was performed using SPSS, version 21.0.

Results: Group I presented a significantly lower MIG (139.2±25.9 vs173.1±33.2 mg/dl, P<0,05) and GV (58.4±18.8 vs 70.3±18.6 mg/dl, P<0.05) and more HT (1.85±1.68 vs 1P30±1.04 h P<0,05). NH episodes weren’t significantly different between groups (8.7 vs 4.8%). HT was positively correlated with GV (r=0.23, P=0.01) and negatively with HbA1C and MIG (r=−0.23 and r=−0.36; P=0.01). NH was correlated with MG (r=−0.24, P<0.05). In multivariate analyses, GV and MIG were associated with HT (β=0.22 and β=−0.15, P<0.01 respectively), independently of HbA1C, diabetes duration and insulin dose; NH was only associated with MIG (OR=0.9, P<0.05). NH was associated with 16-fold increased risk of asymptomatic hypoglycemia (OR: 16.9; P<0.01).

Conclusions: Group I patients presented lower MIG and GV, and more HT than group II. NH episodes weren’t significantly different between groups. An elevated HbA1c wasn’t a reliable indicator of lower risk of hypoglycemia. GV independently predicts daily time duration spent in hypoglycemia.