Preventing Diabetic Retinopathy in Patients with Cardiovascular Risk

A major cause of blindness in the United States is diabetic retinopathy, in which damage to blood vessels in the eye is thought to eventually impair sight. Considering that nearly 11% of U.S. adults are thought to be diabetic, this is a major public health concern in this country. Also discouraging are estimates that type 2 diabetes prevalence is thought to steadily increase over the next several years. The development of blindness can have dramatic effects on quality of life and is an increased burden on the health care system.

Blood glucose control, and the management of both dyslipidemia and blood pressure have been suggested in the literature to curb the development of diabetic retinopathy. A new study published in The New England Journal of Medicine assessed intensive glucose control, dysilipidemia mangament, and intensive blood pressure control in the prevention of diabetic retinopathy.

2,856 type 2 diabetics at high risk for cardiovascular disease were analyzed with the interventions described above. That is, intensive glucose control, lipid management, or intensive blood pressure management. Patients for this study were derived from the ACCORD Glycemia, LIPID, and Blood Pressure studies described elsewhere. In each trial, patients were at high risk for cardiovascular events and the described interventions were assessed for preventing further adverse cardiovascular outcomes. This trial analyzed patients from the above trials in the prevention of diabetic retinopathy for the corresponding intervention.

Intensive glucose therapy, which is maintenance of HbA1c below 6%, led to diabetic retinopathy in 7.3% of patients. However, retinopathy was present in 10.4% of patients receiving standard glucose control, which is maintenance of HbA1c between 7 and 7.9% Likewise, 6.5% of diabetic patients with dyslipidemia treated with fenofibrate developed diabetic retinopathy, in comparison to 10.2% of non-treated patients. Conversely, intensive blood pressure control, which is maintenance systolic blood pressure below 120 mmHg , did not lower diabetic retinopathy (8.8%) in comparison to standard blood pressure control (10.4%), which is maintenance of blood pressure below 140 mmHg, in a statistically significant manner.

This study suggests that in diabetic patients at high risk for cardiovascular events, retinopathy development can be curbed by intensive glycemic control and by adding fenofibrate onto dyslipidemia management. However, lowering blood pressure below what is recommended for standard therapy in diabetics is not efficacious.

References:

The ACCORD Study Group and ACCORD Eye Study Group. Effects of Medical Therapies on Retinopathy Progression in Type 2 Diabetes. N Engl J Med. 2010 Jun 29.

Prevalence of Diagnosed and Undiagnosed Diabetes among People Ages 20 Years or Older, United States, 2007. http://diabetes.niddk.nih.gov/dm/pubs/statistics/index.htm#allages. Accessed 6/28/2010.