Analysis of 24-Hour Glycemic Excursions in Patients with Type 1 Diabetes by Using Continuous Glucose Monitoring

Abstract

Little information is available regarding postprandial glycemic excursions and hypoglycemia in Japanese patients with type 1 diabetes (T1D). Four male and eight female patients who were on intensive therapy with rapid-acting insulin plus basal insulin underwent retrospective continuous glucose monitoring (CGM). Clinical characteristics (median) of the patients were as follows: age, 40.5 years; body mass index, 22.2 kg/m(2); urinary C-peptide, 0.75 microg/day; hemoglobin A1c (HbA1c) after 2 months of CGM, 6.5%; and total insulin dose, 40.0 units. The largest glycemic excursions were observed after breakfast. The time intervals from the start of each meal to the highest postprandial glucose levels peaked at 65-100 min. Hypoglycemia (blood glucose <70 mg/dL) was observed for more than 100 min per 24-h period. HbA1c and 24-h mean glucose levels were significantly correlated (r = 0.727, P = 0.007). The 12 participants were divided into two groups by HbA1c level after 2 months: those whose HbA1c exceeded the median of HbA1c (HbA1c > 6.5%) (n = 6) and those whose HbA1c fell below the median (HbA1c <6.5%) (n = 6). The premeal glucose levels/the highest postprandial glucose levels after breakfast were insignificantly higher in the HbA1c >6.5% group (183/247 mg/dL, respectively) than in the HbA1c <6.5% group (117/221 mg/dL, respectively). The duration of hypoglycemia lasted longer in the HbA1c <6.5% group, with these episodes often occurring during the nighttime. These findings suggest that preventing nighttime hypoglycemia and correcting glucose spikes after breakfast are required in patients with T1D receiving intensive therapy to stabilize and improve glycemic control.