July 16 (UPI) -- Pre-diabetes increases people's risk for heart disease death, especially if they have a history of heart issues, according to analysis published this week by BMJ.
The condition, which is considered a "pre-diagnosis" for diabetes, raises heart disease risk for people with a history of heart trouble by 37%, the researchers said.
Pre-diabetes also increased the risk of death for someone with previous heart issues by 36% over a three-year period, they said.
"Pre-diabetes is associated with an increased risk of all-cause mortality and [heart] disease," wrote the authors, who are from Southern Medical University in China.
The findings suggests that screening adults for -- and properly managing -- pre-diabetes could help prevent heart disease in otherwise healthy individuals and reduce risk for disease progression in those who already have it, they said.
Physicians typically diagnose pre-diabetes when a person's blood sugar level is higher than normal, but not high enough to be considered diabetes, the researchers said.
One in three American adults -- or 88 million people -- are believed to have pre-diabetes, according to the U.S. Centers for Disease Control and Prevention.
Some 70 percent of them will eventually develop type 2 diabetes, the authors of the BMJ analysis said.
For the new study, researchers analyzed the results of 129 studies on links between pre-diabetes and risk for heart or cardiovascular disease and death from any cause in people with and without a history of heart disease. The studies involved more than 10 million people, the researchers said.
In the general population, pre-diabetes was associated with a 13% increased risk for death from all causes and a 15% increased risk for heart disease over an average follow-up period of about 10 years, they said.
In patients with a history of heart disease, pre-diabetes was associated with a 36% increased risk for death and a 37% increased risk for disease progression, over an average follow-up time of around three years, they added.
In addition, impaired glucose tolerance -- or higher-than-normal blood sugar levels after eating -- carried a higher risk for death, coronary heart disease and stroke than impaired fasting glucose, or higher-than-normal blood sugar levels after a period of fasting, they said.