354-P: Interstitial Fluid Glucose as a Measure of Hypoglycemia Burden in Elderly Subjects with Type 2 Diabetes Mellitus

Background: Elderly patients with type 2 diabetes mellitus (T2DM) are at high risk of severe hypoglycemia, but evidence addressing this problem is lacking.

Aims: To assess and compare the burden of exposure to low interstitial fluid glucose (IFG) in elderly subjects with tightly controlled T2DM on sulphonylurea (SU) or insulin therapy.

Methods: Outpatient T2DM subjects ≥65 years of age with HbA1c ≤7.5% were recruited to wear a Freestyle Libre-Pro sensor for 2 weeks. Collected data was analyzed for low IFG burden.

Results: A total of 65 subjects (35 male, 30 female), 72.0 ± 5.0 years old with diabetes duration of 21.4 ± 11.1 years and HbA1c of 6.8 ± 0.5% were recruited; 27 were insulin treated and 38 were SU treated. Patients on insulin had longer diabetes duration (25.4 ± 10.9 vs. 18.0 ± 10.4 years, p<0.05) and poorer kidney function (eGFR 58.6 ± 24.7 vs. 87.3 ± 48.0, p<0.05). Greater proportion of the insulin group performed regular capillary blood glucose (CBG) monitoring (74.1% vs. 29.7%). This group also had more monthly self reported hypoglycemic events (0.85 ± 1.70 vs. 0.14 ± 0.35, p<0.05) and a lower GOLD score (2.42 ± 1.72 vs. 3.73 ± 1.75, p<0.05). While there was no difference in mean number of low IFG events with glucose <72.0mg/dL between the 2 groups (0.92 ± 0.79 vs. 0.59 ± 0.48 events, p value >0.05), very low IFG events with glucose <50.0mg/dL occurred in higher proportions (52% vs. 23%, p<0.05), higher frequency (0.48 ± 0.70 vs. 0.16 ± 0.19 events/person, p <0.05) and for longer durations (1.56 ± 2.94 vs. 0.27 ± 0.43 hours/day, p<0.05) in the insulin group. 62.2% of the SU group and 63.0% of insulin group had at least 1 episode of very low IFG, but none of the SU group and only 2 in the insulin group reported hypoglycemic symptoms.

Conclusion: Low IFG was common among the studied population, with a greater burden in insulin treated patients. Majority were unable to detect events despite regular CBG monitoring suggesting the potential use of IFG in evaluating hypoglycemia burden.