That's according to a new study from Australia.
The study appears online in the rapid access edition of the journal Circulation. The researchers included Elizabeth Barr, MPH, of the International Diabetes Institute in Caulfield, Australia.
About Diabetes and Prediabetes
In prediabetes, the body has started having problems handling blood sugar, but those problems haven't yet become diabetes.
According to the National Diabetes Information Clearinghouse, nearly 21 million people in the U.S. have diabetes, and 90% to 95% of them have type 2 diabetes; 54 million more people have prediabetes.
Many people don't know they have diabetes or prediabetes.
Symptoms of type 2 diabetes may include fatigue, frequent urination, increased thirst or hunger, weight loss, blurred vision, and slow healing of wounds or sores. Some people with prediabetes may have those symptoms, but most people with prediabetes don't have symptoms.
Diabetes, Prediabetes Study
The Australian study included more than 10,400 adults aged 25 and older who were followed for nearly five years, on average.
At the study's start, participants took two tests -- the fasting glucose test and the glucose tolerance test. They were 51-63 years old, on average, at the time. Diabetes becomes more common with age.
For the fasting glucose test, participants fasted for at least nine hours and then provided a blood sample.
For the glucose tolerance test, they drank a sugary beverage and then provided a blood sample two hours later.
Most participants didn't have diabetes or prediabetes. However, 858 had type 2 diabetes, nearly 1,300 others had impaired glucose tolerance, and an additional 610 participants had impaired fasting glucose.
Impaired fasting glucose or impaired glucose tolerance can indicate prediabetes.
Higher Death Rates
During the follow-up period, participants with diabetes or prediabetes were more likely to die of any cause -- especially heart disease.
Compared with people without diabetes or prediabetes, those with diabetes were 2.3 times more likely to die of any cause.
Participants with impaired glucose tolerance or impaired fasting glucose were 50% and 60% more likely to die, respectively, than those with normal glucose.
People with diabetes or impaired fasting glucose were about 2.5 times more likely to die of heart disease than those without blood sugar problems.
Impaired glucose tolerance wasn't specifically tied to heart disease deaths, the study shows.