Hypoglycemia observed during continuous glucose monitoring in patients with type 2 diabetes mellitus treated by subcutaneous insulin injection.

Background: The relationship between hypoglycemia and the dose of insulin used in patients with type 2 diabetes mellitus was investigated by continuous glucose monitoring (CGM). Patients and Methods: In total, 83 CGM studies were performed in 70 outpatients with type 2 diabetes receiving treatment by subcutaneous insulin injection. Results: The total dose of insulin, bolus insulin dose, and basal insulin dose used in the subjects were 32 +/- 18 units, 19 +/- 13 units, and 13 +/- 8 units, respectively. The proportion of time in the hypoglycemic range (blood glucose < 3.9 mmol/L) during CGM was positively correlated with the bolus insulin ratio (bolus/total insulin dose, r = 0.22, P = 0.04), although it was not associated with the total dose of insulin or the hemoglobin A1c (HbA1c) level. It was negatively correlated with the mean blood glucose (r= -0.38, P < 0.01), whereas it was not associated with the SD or the mean amplitude of glycemic excursions (MAGE). The proportion of time in the hypoglycemic range was significantly greater in the subjects with a bolus insulin ratio of >= 0.6 (3.2 +/- 4.4%, n = 42) than a ratio of < 0.6 (1.2 +/- 3.0%, n = 41), although the HbA1c level, total dose of insulin, mean blood glucose, SD, and MAGE were not significantly different between the two groups. Conclusions: An excessive dose of bolus insulin might increase the duration of hypoglycemia, independently from the HbA1c levels, in patients with type 2 diabetes mellitus receiving subcutaneous insulin injection.