Effect of short-term glucose control on glycemic thresholds for epinephrine and hypoglycemic symptoms

Hypoglycemia is the principal barrier to achieving target glucose goals in type 2 diabetes. The effect of short-term improvement in glycemic control on plasma glucose thresholds for symptomatic and hormonal responses to hypoglycemia in type 2 diabetes is not known. We hypothesized that the thresholds for these events would be increased by 1 wk of improved glycemic control in elderly patients with type 2 diabetes. Ten elderly patients with type 2 diabetes were admitted for an 8-d inpatient protocol. All subjects underwent insulin-induced hypoglycemia on days 2 (preglucose control) and 8 (postglucose control). Between days 2 and 8, subjects received intensive diabetes management to improve their glycemic control. Timed blood glucose profiles were obtained daily during the week before and during admission. Plasma glucose; counterregulatory hormones, and hypoglycemic symptoms were assessed at baseline and every 10 min during the hypoglycemic studies. :Mean blood glucose concentrations were significantly reduced by intensive diabetes management from 9.8 +/- 3.7 mmol/liter to 7.7 +/- 3.3 mmol/liter (P < 0.001). The plasma glucose threshold for epinephrine release during insulin-induced hypoglycemia was significantly increased by intensive management from a glucose concentration of 3.7 +/- 0.5 mmol/liter at baseline to 3.1 +/- 0.3 mmol/liter after intensive management (P < 0.05). The plasma glucose threshold for hypoglycemic symptoms was also increased by intensive therapy from a glucose concentration of 5.3 +/- 1.2 to 3.3 +/- 0.6 mmol/liter (P = 0.003). These rapid changes may increase the risk for severe hypoglycemia in type 2 diabetes and limit the ability of physicians to rapidly correct hyperglycemia in elderly type 2 diabetes patients.