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Diabetics Control Glucose, Lower Cardiac Risk

Posted on: Monday, 13 June 2005, 06:00 CDT

SAN DIEGO -- Early, intensive treatment to keep blood sugar levels close to normal in people with diabetes can cut their risk of cardiovascular disease by about 50% and the risk of heart attack and stroke by 57%, much better results than those achieved by any cholesterol or blood pressure drug, researchers reported Sunday.

The finding, which was presented at a meeting of the American Diabetes Association, adds to mounting evidence that the sooner and more aggressively diabetes is treated, the lower the risk of serious long-term complications.

"It's pretty astounding," ADA scientific director Richard Kahn says of the study's results. "This is just major. No other study has shown an effect of glucose control on cardiovascular disease."

The clinical trial involved people with type 1 diabetes, also known as juvenile diabetes, who account for about 10% of the 18.2 million Americans with the disease. Researchers say studies are under way to determine if intensive treatment to reduce blood sugar levels in type 2 patients would have a similar payoff in reducing heart disease.

"There is no reason to think tight glucose control might not be of benefit to the type 2 population," says study co-chair David Nathan, director of clinical research at Massachusetts General Hospital, but that has not been shown in this study. Type 2s average 30 years older than type 1s at diagnosis and often have other heart risk factors such as high blood pressure and obesity, he says.

The study, involving 1,375 patients, is a follow-up to the Diabetes Control and Complications Trial, DCCT, which began in 1983. Participants were given standard care or more intensive treatment, which meant more frequent daily blood testing and insulin injections. Results of that study, reported in 1993, showed that patients who kept tight control of levels of blood sugar, or glucose, for about 6 1/2 years had much lower risk for eye, kidney or nerve damage years later, even if their blood sugar levels rose.

The earlier, the better

The new data show that even more than 10 years after the initial study period, those in the group that kept close control of blood sugar levels early on are less likely to have suffered heart disease.

"Our major observation is if you reduce blood glucose for an extended period, you end up with less cardiovascular disease," says Saul Genuth of Case Western Reserve University in Cleveland, the study's other co-chair.

Reduced risk for heart attack and stroke is greater than that seen in studies of drugs that lower cholesterol or blood pressure, he says.

Another finding is that quick diagnosis and treatment to reduce the duration of high blood sugar levels can lower risk of complications, he says. "The earlier you start intensive treatment, the better."

It's a lesson David Schebler, 55, of Davenport, Iowa, took to heart. He was diagnosed with type 1 diabetes in 1985, when he was 35. "It seemed to come on fast," he says. "I noticed blurry vision, I was thirsty, and had to get up five or six times a night to go to the bathroom. I was losing weight. It seemed to happen in two weeks. It was quite a shock."

Schebler, a certified public accountant, enrolled in the DCCT in 1988 and was assigned to the group that got standard treatment. That meant insulin shots twice a day and blood testing three or four times a day.

When the initial study results were announced in 1993, Schebler says, he immediately switched to intensive control. "The whole upshot was that with tighter control, you reduce complications," he says in a telephone interview.

Schebler began using an insulin pump, a pager-sized device that delivers a steady, measured amount of insulin to the body. He tests his blood sugars up to seven times a day and tracks his readings closely, so he can report trends to his doctor. He watches what he eats, and he exercises by running about five times a week, though "during tax season, my physical activity goes down to zero."

His effort has paid off with good blood sugar control and, so far, no sign of long-term complications.

"It's a lot of work, but that's not to say it's not worth it," Schebler says. "The diabetes isn't going away. It's going to be there 24/7, and you need to stick with the program, watch your food intake, and do what you're supposed to do."

The role of insulin

Genuth says the benefits of early tight control of blood sugars also might apply to people with type 2 diabetes, though there is some evidence from other research that in type 2, the body's resistance to the action of its own insulin may in itself promote heart disease, independent of blood sugar level.

Although that DCCT follow-up study shows that keeping blood sugars low for 6 1/2 years led to lower risk for heart disease, Genuth says, how and why that occurs "we can't say. We don't know the mechanism by which having higher blood glucose causes cardiovascular disease."

But, Genuth adds: "I want to be clear that our research group is not saying that all you have to do is have intensive treament for 6 1/2 years and you're home free.

"We believe intensive treatment should start as early as possible and be maintained as long as possible."

Source: USA TODAY

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