Updated July 25, 2014.
It's 2014 as a write this, and I'm still hearing about "that study that showed that diabetics shouldn't try to get their blood sugar down to normal". They are talking about the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study, and it truly showed no such thing. People with diabetes write to me because they are worried that a low-carb diet might normalize their blood glucose too much.
What was the ACCORD study?
The ACCORD study was a large study looking at over 10,000 diabetic patients who were at high risk for cardiovascular disease. It had three different interventions to try to lower disease risk. The first one involved using medications in a more agressive way than usual to try to lower blood glucose (as measured by HbA1C) to closer to normal than is usually recommended. This involved, among other things, higher doses of medications than usual.It has definitely been established that the higher the blood sugar, the higher the risk for complications of diabetes (eye disease, kidney disease, neuropathy, amputations, etc.), disabilities, and heart disease. However, the recommended target blood glucose level for diabetics (generally an HbA1C of between 7% and 8%) is not the same as the level that is considered normal blood sugar (below 5.6% is normal, between $5.7% and 6.4% is prediabetic, and 6.5% and above is diabetic). The blood glucose part of the ACCORD study sought to find out whether targeting a blood glucose below 6 would produce a lower risk of heart attacks, strokes, and death from cardiovascular disease.
Why did they discontinue the blood glucose control arm of the ACCORD study?
Instead of lowering the risk of cardiovascular events, people in the intensive-blood-glucose-control group actually had a higher risk of death from cardiovascular disease, as well as other causes of death. Therefore, in 2008 that arm of the study was discontinued.
We do not know what precisely caused the increased death rate, but the researchers have been clear that they do not think the fault was the goal (better blood sugar control). Rather, the problem was almost certainly the way in which this was achieved. It could have been the increased levels of medications. Michael Eades of the Protein Power diet books has some interesting speculations that increased medications could have led to higher consumption or carbohydrate, which lead to higher insulin levels, which is a risk for heart disease. Other people have other theories. But no one thinks that lowering blood glucose with diet and exercise is dangerous. Unfortunately media reports about the study almost always led with the idea that "intensive blood glucose control led to more deaths".
Were there other similar studies, and what did they show?
A similar study in Austalia did not show the same increase in death rate.What do the results of the ACCORD study mean to the average diabetic person?
First of all, again, we KNOW that blood glucose control prevents the many many health problems that can result from diabetes. For example, a sample of patients from the same study were followed to check for damage in the eye (retinopathy, which can lead to blindness). Those patients who were in the "intensive blood glucose control" group had a 30% lower progression in eye damage over 4 years compared those with traditional blood glucose goals.The conclusion that most medical organizations have come to is simply that treatment for diabetes needs to be personalized according to severity and complications of diabetes, responses to various treatments (including side effects), and motivation of the patient.
I read a lot about this study, and nowhere did I hear the recommendation to increase the support for making lifestyle changes (primarily diet and exercise). This, to me, is disturbing, as these changes are totally safe provided that the diet is nutritious and the exercise is tailored to the individual. We know that in other conditions that require significant dietary changes (e.g. celiac disease, soy allergies) that with proper support people are able to make these changes. We also know that carbohydrate reduction can produce much improved blood glucose control in most diabetics. But all too often, health care providers throw up their hands, and precriptions end up taking the place of lifestyle changes. These changes admittedly take effort on the parts of both the health care providers and patients. But we are talking about avoiding blindness, dialysis, amputation, and other disabilities. What could be more worth it?
Sources
The ACCORD Study Group and ACCORD Eye Study Group. "Effects of Medical Therapies on Retinopathy Progression in Type 2 Diabetes." New England Journal of Medicine 2010; 363:233-244
Dluhy, RG and McMahon, GT. "Intensive Glycemic Control in the ACCORD and ADVANCE Trials." New England Journal of Medicine 2008; 358:2545-2559
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