Regimen slows diabetic complications.

By keeping blood sugar concentrations as close to normal as possible, people with Type 1 diabetes can prevent or slow the file-threatening complications of this disease, according to a new study An independent review panel halted the research after nine years -one year short of its planned length- because preliminary analysis of the data revealed such substantial benefits for people with Type I diabetes that continuing the study seemed unnecessary.

The findings surprised some researchers, who didn't expect to see such dramatic results. "I think we hit a home run. You can substantially reduce the risk of progression," says Julio V. Santiago, a diabetes specialist at Washington University in St. Louis and one of the study's principal investigators.

Type 1 diabetes, like other forms o! the disease, makes it difficult for the body to process glucose, a simple sugar and the main source of energy for cells. People with Type I diabetes must get daily injections of the hormone insulin in order to use glucose in their bloodstream.

For years, some researchers had argued that by keeping a tight rein on glucose concentrations in the blood, patients could slow the development of medical conditions associated with diabetes. Those complications include retinopathy, a blinding disease in which tiny blood vessels in the retina begin to leak; nephropathy, in which blood vessels in the kidney are damaged; and neuropathy, in which nerves in the feet, legs, and fingertips are damaged.

Before advising diabetic patients to embark on more complicated treatment regimens, researchers had to confirm that tight control of blood glucose really provided significant gains. Thus, the National Institute of Diabetes and Digestive and Kidney Diseases sponsored a trial of 1,441 people with Type I diabetes, which usually develops before age 30.

Researchers at 29 medical centers throughout the United States and Canada randomly assigned volunteers, who had no complications or mild complications at the study's start, to either a standard treatment or a rigorous therapy group.

People getting standard care received one or two shots of insulin daily but did not make any extraordinary effort to keep blood sugar concentrations low.

By contrast, volunteers assigned to the more rigorous group received three or more injections of insulin per day or relied on a small, battery-powered device called an insulin pump to continuously deliver insulin through a tiny needle inserted under the skin. Volunteers assigned to this group had to measure their blood sugar four times a day and then adjust their insulin intake accordingly. This regimen more closely resembles the way the body regulates glucose.

The researchers found that people getting the standard therapy had about 231 milligrams of glucose per deciliter of blood, an amount that far exceeds the norm of 110 mg/dl but falls within the usual range for diabetics. By contrast, people in the rigorous therapy group had glucose concentrations of about 155 mg/dl.

Despite the fact that their blood sugar was higher than normal, people in the rigorous therapy group experienced a 60 percent reduction in the risk of complications. Those results, which experts say will revolutionize the treatment of diabetes, were announced this week at the American Diabetes Associations annual scientific sessions held in Las Vegas.

Compared to the standard therapy the new treatment delayed the onset or slowed the progression of retinopathy by 76 percent. It also prevented or delayed progression of kidney disease by 35 to 56 percent, the researchers found. And rigorous treatment forestailed nerve damage that can lead to loss of sensation in the feet, legs, and fingertips.

Diabetics following the more exacting regimen also shouldered some risks. The trial revealed that people in the experimental therapy group faced three times the risk of developing hypoglycemia, a condition in which concentrations of blood sugar dip too low. These attacks can cause shakiness, disorientation, and in severe cases, coma.

Most Type I diabetics can reduce their risk of hypoglycemic attacks, adds James R. Gavin III, newly elected president of the American Diabetes Association. The danger of hypoglycemia can be reduced by frequent monitoring of blood sugar, fine-tuning of insulin dosage, and changes in diet and exercise, he says.

The new study focused on Type I diabetes patients, but many scientists think more rigorous glucose control may also benefit people with Type II diabetes, which generally strikes after age 40. Excessive glucose in the blood may also cause the eye, kidney, and nerve complications that afflict these people.