The studies, presented to a meeting of the American Diabetes Association, show that early symptoms of diabetes and heart disease must be treated aggressively, experts said.
These symptoms occur in "metabolic syndrome" -- an aggregate of risk factors such as obesity, high cholesterol and other symptoms.
"If we could just detect and treat the metabolic syndrome...we could reduce heart attacks in this country by 63 percent," said Dr. David Eddy of Archimedes Inc., a company that makes computer-based analysis and decision-making tools.
Curing insulin resistance alone would reduce heart attacks by 42 percent, Eddy told a news conference.
Normal blood glucose levels are 70 to 110 mg/dL, and anything higher is often considered insulin resistance or impaired fasting glucose.
Eddy's company is working on a computer program that would help doctors predict which heart risk factors are the most important for their individual patients.
Nearly 21 million Americans have diabetes, most of them type-2 diabetes. But the National Institutes of Health last month estimated that one third of these people do not know it.
"We found that people with pre-diabetes clearly have an excess of cardiovascular risk factors," Dr. Desmond Williams, a diabetes expert at the U.S. Centers for Disease Control and Prevention told the news conference.
His team examined interviews conducted as part of an annual national health survey. Of the 3,000 healthy adults ages 20 to 75, 28 percent had pre-diabetes, he said -- defined as fasting blood glucose levels between 100 and 125 mg/dL.
HOSPITAL DEATHS
Dr. Mercedes Falciglia of the University of Cincinnati College of Medicine in Ohio found that non-diabetic patients with high blood sugar who also had a heart attack, stroke or chest pain were much more likely to die than other patients with the same conditions.
Her team studied 216,000 severely ill patients admitted to 177 Veterans Affairs intensive care units.
Falciglia's team defined hyperglycemia as blood sugar levels of 111 or higher. Hyperglycemia raised the risk of heart attack death by up to five times and the risk of death from stroke as much as 15-fold, she told the meeting.
"All patients should have their blood glucose levels monitored when they are admitted to an intensive care unit because hyperglycemia occurs in one third of ICU patients," Falciglia said.
The CDC's Dr. Venkat Narayan and colleagues looked at a person's lifetime risk of diabetes based on weight. "The average lifetime risk for diabetes for a normal weight male aged 18 years is 20 percent," Narayan said.
This increased to 57 percent for an obese male and 70 percent for a very obese male. The numbers are similar for females.
In the United States, more than 60 percent of the population is overweight and 30 percent is obese.
The Diabetes Association's Dr. Robert Rizza said diet and exercise is the place to start controlling this. "But in the meantime don't tolerate high blood (cholesterol or) high blood glucose," Rizza said. He said drugs should be used to control abnormalities in people who cannot or will not lower them with diet and exercise.