Investigation of the Risk Factors for Severe Hypoglycemia Unawareness in Patients with Type 1 Diabetes Using Continuous Glucose Monitoring System (CGMS)

Abstract

Background/Aim: Low blood glucose index (LBGI), a predictor of hypoglycemia, is evaluated by self-measurement of blood glucose (SMBG). We investigated whether LBGI from short-term continuous glucose monitor (CGM) could also predict severe hypoglycemia (SH).

Subjects and Methods: Type 1 diabetic patients (n=250, 75 men) with HbA1c <10 % who consented to using a CGM were recruited. Twenty patients were treated with insulin pump and the rest with multiple daily injections of insulin. Blood glucose fluctuation index was compared between group A, with SH unawareness and group B with SH awareness, and the correlation factors with LGBI was investigated.

Results: Group A, with a longer duration of diabetes than group B, displayed significantly higher J-index, average daily risk range (ADRR), mean of daily difference of blood glucose (MODD), and LBGI. Both LBGI and MODD were independent risk factors for SH unawareness by multiple regression analysis (OR: 1.20, 1.04; p = 0.043, 0.002, respectively).

Discussion: The LBGI from CGM data can be predictive of SH. Even without SH, some patients in group B displayed high LBGI values. MODD and ADRR in group A were also significantly lower than in group B. This suggested that SH unawareness might occur in patients with larger daily and diurnal blood glucose variations.