The question: Studies have shown that having diabetes makes a person more susceptible to heart failure, which occurs when the heart can't pump sufficient amounts of blood throughout the body.
But does the combination of these disorders increase the risk of death?
The latest: This study examined the medical records of 554 people with heart failure who were evaluated for a possible heart transplant.
In the group of mostly men, 132 people were diabetic (most of them with type 2 diabetes), with 43 (about a third of the diabetics) treated with insulin.
People with heart failure who used insulin were four times more likely to die within a year than the others.
Those who treated diabetes with oral medications - such as a sulfonylurea, metformin or glitazone - had similar mortality rates as non-diabetics.
One-year survival rates were 90 percent for non-diabetics, 86 percent for diabetics not treated with insulin and 62 percent for those who used insulin.
Who may be affected by these findings?
People with heart failure and diabetes, a dual condition that affects up to 2 million Americans.
Caveats: The number of participants was small and included only people with more advanced heart failure.
Their use of different heart failure medications may have affected the results.
The study did not determine whether the oral diabetes drugs offered any cardiovascular benefits that altered the findings.
Bottom line: People who have both heart failure and diabetes may want to talk with a doctor about ways to control the diabetes before insulin injections become necessary.