The aim of this study to investigate whether the occurrence of nocturnal severe asymptomatic hypoglycemia (NH) may be predicted based on glycemic variability on the previous day and next morning on the day of onset. This study examined patients with type 1 diabetes (T1D) who underwent CGM assessments and received basal bolus therapy of insulin degludec (IDeg) in outpatient setting. NH was defined as glucose levels < 54 mg/dL detected between 12:00 and 6:00 AM. The subjects were evaluated for fasting glucose level, the range of post-breakfast glucose elevation, and glucose level at bedtime (12:00 AM) on the previous day. For comparison, the patients were divided into those with NH and those without by using t-test. Optimal cut-off values for the relevant parameters were determined in order to predict NH using ROC analysis. Thirty-one patients (mean HbA1c values, 7.8 ± 0.7 %) were selected for analysis. NH occurred in 8 patients (26%). Fasting glucose level was significantly lower in those with NH than in those without (61 ± 13 mg/dL vs. 130 ± 68 mg/dL; P = 0.001). The range of post-breakfast glucose elevation was significantly greater in those with NH. Again, the glucose level at bedtime was significantly lower in those with NH than in those without (88 ± 44 mg/dL vs. 144 ± 69 mg/dL; P = 0.044). The cut-off values for predicting NH determined for the relevant factors were as follows: fasting glucose level < 69 mg/dL (sensitivity 0.83/ specificity 0.75/ AUC 0.86, P = 0.003) and bedtime glucose level < 90 mg/dL (0.83/ 0.75/ 0.79, P = 0.017). The results suggest that fasting glucose level of < 69 mg/dL and bedtime glucose level < 90 mg/dL had approximately 80% probability of predicting the occurrence of NH in T1D receiving IDeg. While the post-breakfast glucose levels and the pre- and post-dinner glucose levels were not significantly different, the range of post-breakfast glucose increase was greater in those with NH than in those without.


H. Takahashi: None. R. Nishimura: Speaker's Bureau; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Astellas Pharma US, Inc., Eli Lilly and Company, Abbott, Medtronic, MSD K.K., Novo Nordisk A/S, Sanofi, Takeda Development Center Asia, Pte. Ltd., Kissei Pharmaceutical Co., Ltd., Taisho Pharmaceutical Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd.. K. Utsunomiya: None.

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