Glucose Control and Vascular Complications in Veterans with Type 2 Diabetes

Introduction:  How intensive blood glucose control affects cardiovascular events in patients with long-standing type 2 diabetes is still uncertain.

Methods:  The study involved 1,791 military veterans (mean age, 60.4 years) who had a sub-optimal response to treatments for type 2 diabetes.  11.5 was the mean number of years since diagnosis.  They were randomly assigned to either an intensive blood glucose control group or a standard blood glucose control group.  Cardiovascular risk factors were treated uniformly.  40% of the patients had already experienced a cardiovascular event.

In the intensive-therapy group, the goal was an absolute reduction of 1.5% in the glycated hemoglobin (HbA1c) level, as compared to the standard-therapy group.

The primary outcome assessed was the time from randomization to the first major cardiovascular event, which was a composite of myocardial infarction, stroke, death from cardiovascular causes, congestive heart failure, surgery for vascular disease, inoperable coronary disease, and amputation for ischemic gangrene.

Results:  There was a median follow-up of 5.6 years.  In the standard blood glucose control group, the median HbA1c level was 8.4%; in the intensive blood glucose control group, it was 6.9%.  The primary outcome happened in 264 patients in the standard-therapy group; it occurred in 235 patients in the intensive-therapy group (hazard ratio in the intensive-therapy group, 0.88; 95% CI, 0.74-1.05; p=0.14).  Between the two groups, there was no significant difference in any component of the primary outcome or in the rate of death from any cause (hazard ratio, 1.07; 95% CI, 0.81-1.42; p=0.62).  Also, there was no difference between the two groups for microvascular complications.  The rates of adverse events—primarily hypoglycemia—were 24.1% in the intensive-therapy group and 17.6% in the standard-therapy group.

Conclusions:  In patients with poorly controlled type 2 diabetes, intensive blood glucose control had no significant effect on the rates of major cardiovascular events, death, or microvascular complications; the exception to this is in the rate of albuminuria (p=0.01).