Should we be relaxed about glucose control in diabetes?
The underlying problem in diabetes is that the blood glucose levels are too high, either due to lack of insulin production or resistance to the effect of insulin. While I was at medical school, two studies changed practice in diabetes: DIGAMI and UKPDS.
The UK Prospective Diabetes Study (UKPDS) found that intensive blood-glucose control by either oral agents or insulin reduced the risk of the so-called “microvascular” complications (i.e. kidney disease, retinal disease and neuropathy), but not macrovascular disease (heart attacks and stroke) in patients with type 2 diabetes. The study led to a focus on the microvascular complications of diabetes.
The DIGAMI (Diabetes and Insulin-Glucose Infusion in Acute Myocardial Infarction) study suggested that after heart attacks, all diabetic patients should receive intensive glucose control with an insulin/dextrose infusion, even if they were not usually on insulin. This study meant that all diabetic patients with MI were put on insulin infusions for 48 hours after their MI. The DIGAMI-2 trial and other later studies have not been so clear- cut in their results and so this practice has largely stopped.
Although a recent meta-analysis has shown that diabetes leads to a doubling in the risk of vascular disease (including MI), independently from other conventional risk factors, fasting blood glucose levels are, AT BEST, modestly associated with this risk. The authors of that meta-analysis concluded that “In people without a history of diabetes, information about fasting blood glucose concentration or impaired fasting glucose status did not significantly improve metrics of vascular disease prediction when added to information about several conventional risk factors”.
Another meta-analysis of 5 trials of intensive versus standard glucose-lowering therapies found no difference in effect on stroke or death, but a 17% reduction in non-fatal heart attacks.
In diabetic patients, the benefits of intensive glucose control do not seem to be as great as initially thought, whether in primary (before a heart attack) or secondary (after a heart attack) prevention. If you had to treat anything intensively, I would go for Intensive blood pressure control which is a more effective treatment in reducing vascular disease in these patients.