"Results of a study reveal a "rather striking" association between diabetic retinopathy, particularly proliferative diabetic retinopathy, and the presence and extent of coronary artery calcium (CAC), a reliable indicator of atherosclerosis, researchers report in the May issue of Diabetes Care.

"If confirmed in other studies, identifying type 2 diabetic patients with proliferative diabetic retinopathy may help ascertain who is at uniquely high risk for clinical cardiovascular disease," the team concludes.

Dr. Peter D. Reaven from the Carl T. Hayden Veterans Affairs Medical Center, Phoenix, Arizona and colleagues analyzed the relationship between retinopathy and CAC in a subsample of 204 type 2 diabetics in the VA Diabetes Trial.

The majority of the study subjects were male (95 per cent) and non-Hispanic white (70 per cent), with a mean age of 62 years and a mean duration of diabetes of 12.3 years. Most were hypertensive (80 per cent) and had a history of smoking (70 per cent) and 39 per cent had some prior history of cardiovascular disease.

Retinopathy was correlated with CAC (p = 0.006) and CAC scores increased across retinopathy categories, Dr. Reaven and colleagues report. The median CAC score was 197 in subjects with no retinopathy, 229 in those with microaneurysms only, 364 in those with mild nonproliferative diabetic retinopathy and 300 in subjects with moderate to severe nonproliferative diabetic retinopathy.

Most strikingly, the researchers say, the median CAC score was 981 in individuals with proliferative diabetic retinopathy (p < 0.01).

On logistic regression analysis, the presence of proliferative diabetic retinopathy was associated with an odds ratio of 6.2 of having a CAC score greater than 400 -- "a value that is increasingly recognized as placing individuals at a particularly high risk for future clinical cardiovascular events," Dr. Reaven and colleagues note.

"These data," the team concludes, "indicate an important relationship between retinopathy and extent of CAC and suggest the potential to identify and treat shared risk factors for these common micro- and macrovascular complications."