Glycemic Variability: Can We Bridge the Divide Between Controversies?

What does it take to put glucose variability into or out the heart of glycemic disorders in type 2 diabetes? By analyzing the database of the Hyperglycemia and Its Effect After Acute Myocardial Infarction on Cardiovascular Outcomes in Patients With Type 2 Diabetes Mellitus) HEART2D trial, a premonitory acronym, Siegelaar et al. (1) have reported in this issue of Diabetes Care that glycemic variability cannot be placed at the heart of the risk factors implicated in the progression of cardiovascular diseases in people with type 2 diabetes. The HEART2D trial (2) was initially designed to know whether control of basal hyperglycemia or postprandial hyperglycemia is best for reducing cardiovascular outcomes in patients with type 2 diabetes who had a history of myocardial infarction. In order to answer this question, the investigators of the HEART2D trial have enrolled poorly controlled type 2 diabetic patients who had experienced acute myocardial infarction. Patients were further assigned to either a basal insulin strategy that targeted fasting and interprandial glycemia or an insulin regimen with three daily injections of a rapid insulin analog at premeal times in order to target postprandial glucose excursions. A similar lowering effect on ambient (sustained chronic) hyperglycemia assessed by HbA1c levels was observed with the two insulin regimens. No difference in the incidence of cardiovascular events was detected between the two regimens despite that the prandial group had lower postprandial glycemia compared with the basal group at interim analysis, when the study was halted after a mean follow-up of 2.7 years. Even though the authors of the HEART2D trial did not perform any specific assessment of glycemic variability, a rapid glance at the 7-point glycemic profile seems to indicate that the range of glycemic variability was different between the prandial and basal insulin regimens at study end. The analysis …