MONDAY, April 14, 2008 (HealthDay News) -- Diabetic retinopathy, a leading cause of vision loss in the United States, is also a warning sign of heart failure, a new study says.
The study followed more than 1,000 middle-aged people with type 2 diabetes for nine years and found that those with retinopathy at the start had more than a 2.5-fold higher risk of developing heart failure than those without retinopathy.
The finding was published in the April 22 issue of the Journal of the American College of Cardiology.
"They have made the point that patients with diabetic retinopathy need to be more vigilant in looking for the development of heart failure," said Dr. Hector O. Ventura, director of the cardiology residency program at the Ochsner Health System in New Orleans, and co-author of an accompanying editorial in the journal.
The physical connection between retinopathy -- which is caused by leakage and/or overgrowth of tiny blood vessels in the eye -- and heart failure -- which is the progressive loss of the ability to pump blood -- is not clear, Ventura said. But the new study strengthens evidence for such a link, he said.
A relationship between diabetic retinopathy and an increased risk of heart failure was first described two decades ago in the long-running Framingham Heart Study, which follows residents of a Massachusetts city, the journal report noted.
A number of later studies found a similar relationship. The research team behind the new study, an international group with members in Australia, Singapore and the United States, described the retinopathy-heart failure association in detail two years ago in a study of people with diabetes in four communities.
The new study singled out retinopathy as a heart risk factor by selecting participants who were free of kidney disease and coronary heart disease, two major risk factors for heart failure.
Just 125 of the participants had diabetic retinopathy at the start of the study. After nine years, heart failure was diagnosed in 27 of them, an incidence of 21.6 percent. The incidence in those without the eye condition was 8.5 percent.
Guidelines for treatment of retinopathy do not mention heart failure, but perhaps they should, Ventura said. "Maybe the guidelines one day will say that if you have retinopathy, you should see a cardiologist," he said.
It's possible that the same kind of trouble with the eyes' microvasculature -- the tiniest blood vessels -- can also have an effect on the heart over the decades, the study authors said.
Retinopathy could be an indicator of inflammation and other damage to the endothelium, the delicate inner lining of blood vessels, Ventura said.
Dr. Nancy Sweitzer, director of the heart failure program at the University of Wisconsin, said, "The interesting thing about this study was that the association was as strong for mild degrees of eye disease as for strong degrees. It has to be taken very seriously."
While the study doesn't break new ground, she said, "no one has ever looked in such a detailed way at the association between disease in microvessels and heart failure."
Cardiologists have become more concerned about the coronary effects of diabetes in recent years, and people with diabetes should act on that concern, Sweitzer said. "They should talk to their doctor about diabetes in general, not just about retinopathy," she added.
Learn more about diabetic retinopathy from the U.S. National Eye Institute.