Data from the massive ACCORD study on intensive blood sugar control shows that lowering blood sugar levels in people with longstanding type 2 diabetes to near-normal may delay the appearance of signs that point to damage to nerves, eyes, and kidneys, but does not stop their progression toward it.
What happens instead is that while long-term damage seems inevitable, intensive blood sugar control may somewhat lessen that damage. After ACCORD’s experiment with intensive control (an A1c goal of 6% or less) was halted in 2008, people who had undergone it showed less deterioration in a vision test and underwent 20 percent fewer cataract surgeries than people in the standard treatment group. They also showed 30 percent less leakage of protein into their urine, a sign of kidney disease and a marker for future heart problems.
ACCORD (Action to Control Cardiovascular Risk in Diabetes) was a National Institutes of Health-funded study that began in 2001. The study tracked 10,251adults with type 2 diabetes to see if intense blood sugar control could delay the onset of cardiovascular problems caused by inflammation.
At the time, enrolled participants averaged 62 years of age, were obese, and had had type 2 an average of 10 years. About one-third had heart disease and the remainder carried at least two risk factors for cardiovascular disease. Half of them had A1c’s of 8.1%, well above the 7% level recommended by the American Diabetes Association as “ideal” for people with type 2, and far above the below 6% figure for people without diabetes.
Participants in the intensive control category all received treatments designed to drive their blood sugar levels to near-normal. Further treatment included either intensive blood pressure control or blood lipid treatments designed to lower “bad” cholesterol and elevate “good” cholesterol.
The A1c target for the intensive control group was less than 6 percent, a level approaching that of adults who do not have diabetes. In contrast, 7% to 8% is considered an acceptable A1c range for people with type 2 diabetes. Both the intensive-control and standard-treatment groups in the study were treated with FDA-approved medications.
By 2008, researchers became alarmed when they saw that participants in the intensive blood sugar control group were running a 22 percent greater risk of death than members of the control group that were receiving standard blood sugar control therapy. (The absolute risk of death was 5 percent for the intensive group’s members and 4 percent for the non-intensive control group.) They also found that the intensive group ran a three-times-higher risk of hypoglycemia than members of the control group (10.5 percent versus 3.5 percent overall).
Although researchers halted the intensive-control portion of the study, they continued to track post-study effects of lowered blood sugar levels on the development of eye, nerve and kidney complications. That’s when they found that although people with longstanding type 2 inevitably progress toward such complications, their severity may be lessened somewhat by intensive control.
One explanation for the increased death rate among intensive-control patients is that they may have been vulnerable to a dramatic change in treatment given their age, obesity, and the long time that they’d had diabetes. Some recent studies have called into question whether people who have type 2 for years can or need to achieve A1c levels below 7% without unduly risking their health.
Although the reasons why this is so are not clear, it may have to do with the body habituating itself to higher blood sugar levels and “learning” to live with them. Attempts to dramatically decrease those levels may cause a stress reaction that actually makes people more vulnerable to the cardiovascular problems lower A1c’s were intended to avoid.