Near-normal blood sugar target did not delay risk of organ damage in people with diabetes

In people with longstanding type 2 diabetes who are at high risk for heart attack and stroke, lowering blood sugar to near-normal levels did not delay the combined risk of diabetic damage to kidneys, eyes, or nerves, but did delay several other signs of diabetic damage, a study has found. The intensive glucose treatment was compared with standard glucose control.

These findings are from the NIH-funded Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Although intensive treatment produced some beneficial changes, this approach was reported in 2008 to increase death rates.

The new ACCORD findings appear June 29, 2010 in The Lancet's special online diabetes issue, coinciding with a presentation of the study results at the American Diabetes Association's 70th annual scientific sessions in Orlando.

Over time, diabetes damages the small blood vessels of the eyes, nerves, kidneys and other organs, leading to pain and disability. Heart disease due to damaged large blood vessels is a major cause of death in persons with type 2 diabetes. The longer a person has diabetes, the greater the chances of serious complications, including vision loss and blindness, foot ulcers and amputations, kidney disease and kidney failure, and heart disease and stroke.

"In these ACCORD participants with established type 2 diabetes and additional risk factors for cardiovascular disease, intensive lowering of blood glucose reduced some markers of eye, nerve and kidney disease compared with standard glucose control, but the groups did not differ in the rate of progression to kidney failure, nerve disease, and major vision loss," said lead author Faramarz Ismail-Beigi, M.D., Ph.D., of Case Western Reserve University, Cleveland.

The ACCORD clinical study compared the effect of intensive control of blood sugar, blood pressure, and blood lipids to standard, less-intensive treatments on the risk of major cardiovascular events in more than 10,000 adults with established type 2 diabetes. The study's intensive glycemia arm was halted in February 2008 due to excess deaths in that group. At that time, participants in the intensively treated group were moved to standard glucose control.

At enrollment, ACCORD participants averaged 62 years of age and were obese. In addition to having type 2 diabetes for an average of 10 years, about one-third had pre-existing heart disease, and the remainder had at least two additional cardiovascular disease risk factors. They also had high blood sugar, as measured by the hemoglobin A1C test, which shows average blood sugar in the preceding two to three months. Half of participants had an A1C over 8.1 percent— above the currently recommended target for good control. A1C values in people without diabetes are less than 6 percent.

Previously reported results showed that over about three-and-a-half years of follow up, participants in the intensive blood sugar group had a 22 percent higher risk of death (5 percent versus 4 percent) and a three times higher risk of seriously low blood sugar (10.5 percent versus 3.5 percent) compared with participants in the standard blood sugar control group.