Relationship among A1C, hypoglycemia, and hyperglycemia in Japanese with type 2 diabetes--results from continuous glucose monitoring data.

Background: The intensive treatment aimed at achieving optimal A1C may increase a risk of hypoglycemia. Therefore, we examined the rate and duration of hypoglycemia (<70 mg/dL) and the duration of hyperglycemia (≥200 mg/dL) according to their A1C status, using continuous glucose monitoring (CGM) in Japanese patients with type 2 diabetes who were treated with hypoglycemic agents.

Methods: Forty subjects were equally divided into three groups according to their A1C levels (low, intermediate, and high A1C groups). The 24-h CGM data were collected immediately upon admission to hospital with the patients continuing to take the same medications they had prior to hospitalization.

Results: There was a significant difference in the total duration of hyperglycemia among the groups, with the low A1C group having a median duration of hyperglycemia of 50 min (25-75(th) percentile, 0-550 min) compared with 302.5 min (220-500 min) in the intermediate A1C group and 660 min (185-830 min) in the high A1C group. However, the incidence rate and total duration of hypoglycemia were similar for all A1C groups.

Conclusion: The A1C level did not predict the presence or the duration of hypoglycemia.