Pre-diabetes lurks

By Terri Coles

TORONTO (Reuters) - Millions of Americans have pre-diabetes, a condition that raises their risk of developing heart disease and type 2 diabetes, and many have no idea.

People with pre-diabetes have blood glucose levels that are elevated but not high enough to be diabetes; they have some pancreatic function -- the pancreas still makes insulin to regulate blood sugar levels but can't make enough to keep them from rising.

But many pre-diabetics are unaware of their condition because it usually doesn't present with any specific symptoms or side effects.

"Pre-diabetes is sort of this middle ground between normal glucose metabolism and diabetes," said Dr. Lori Roust, a physician with the Mayo Clinic's Graduate School of Medicine in Rochester, Minnesota.

Though most patients aren't informed about the condition, it's quite common, Roust said. A recent Mayo Clinic report estimated that 54 million Americans are pre-diabetic, representing a large portion of the population who are at risk for developing type 2 diabetes. Many pre-diabetics develop type 2 diabetes within 10 years.

There are two ways to measure pre-diabetes, said Dr. Thomas Hoerger, a senior fellow at RTI International, a research institute in North Carolina: impaired glucose tolerance and impaired fasting glucose. It's estimated that about 25 percent of overweight adults aged 45-75 show both of those signs, Hoerger said.

The prevalence of pre-diabetes in that population is estimated at 20 to 25 percent.

The most obvious risk of pre-diabetes is that it will develop into type 2 diabetes, bringing a variety of associated health concerns, including kidney problems, heart disease, blindness and nerve damage. But just being pre-diabetic is also related to an increased risk of heart disease, Roust said.

As well, people who are pre-diabetic often show a host of associated health conditions, including gestational diabetes, hypertension and hypertriglyceridemia.

Some minority groups, such as Hispanics, Native-Americans and African-Americans, are also at a higher risk of developing diabetes, Roust said, and Pacific Islanders and Asian-Americans show higher insulin resistance at lower body weights.

Pre-diabetes is detected with a simple blood test to measure blood sugar, a test that is commonly covered by most health insurance plans, Roust said. But Hoerger adds that despite the ease and relatively low cost of testing, many people aren't being screened for pre-diabetes.

Intervention to screen and treat pre-diabetics increases overall health costs but it also improves health outcomes, said Hoerger, lead author of a study that showed screening for pre-diabetes was cost-effective.

The study showed that screening and intervention in overweight and obese adults aged 45-74 who had both impaired glucose tolerance and impaired fasting glucose would cost the health care system $8,181 to gain one quality-adjusted life-year.

That's well below the common benchmark ratio of $50,000 per quality-adjusted life-year, he said, suggesting that screening for pre-diabetes is a good use of health care dollars.

"We're paying more," Hoerger said, "but we're getting more."

Type 2 diabetes isn't inevitable for pre-diabetics, said Roust. Patients who are screened and discover they are pre-diabetic can prevent type 2 diabetes by improving their diet and activity level, she said.

She generally recommends getting at least 30 minutes of moderate aerobic exercise five times a week.

A dietician can help patients evaluate their diet and point out areas where improvements could be made. A previous type 2 diabetes trial found that a 7 percent weight loss -- 14 pounds for a 200-pound person -- through dietary changes and increased physical activity reduced the risk of developing the disease by nearly 70 percent, she said. Even if a person's weight doesn't change, increasing muscle mass relative to fat mass will have an effect, because muscle is more sensitive to insulin resistance.

"I stress to patients that with some attention to lifestyle, they can really, really have dramatic effects at preventing the progression to diabetes," Roust said. "And it is much easier to prevent diabetes than it is to treat it after it's developed."

Terri Coles writes about health and wellness issues for Reuters.com. She's based in Toronto. You can reach her at healthmatters@reuters.com