Diabetes mellitus is a complex, multifactorial disease that is often associated with progressive retinopathy and visual loss. In Diabetes and Ocular Disease: Past, Present, and Future Therapies, 2nd edition, edited by Ingrid U. Scott, MD, MPH, Harry W. Flynn, Jr., MD, Dr. William E. Smiddy, MD, readers have a practical reference for the diagnosis and management of ocular disease in diabetic patients. In the excerpt below, from the opening essay by Robert E. Leonard II, MD, and David W. Parke II, MD, we learn about the consequences of diabetes.
Treatment of complications due to diabetes is a growing source of health care expenditures. While ophthalmologists focus on the retinal and ophthalmic complications of diabetes and their treatment costs, it is important to note that these represent only a fraction of the overall costs of uncontrolled diabetes. Chronic complications of diabetes include accelerated atherosclerosis and its associated macrovascular disease processes of CHD, stroke, and peripheral vascular disease. These are responsible for the majority of diabetes-associated morbidity and mortality. Peripheral and autonomic neuropathy, renal impairment and failure, and diabetic retinopathy are associated with the microvascular complications of diabetes. As an example, Haffner and colleagues compared the 7-year incidence of myocardial infarction (MI) in diabetic and nondiabetic subjects with and without prior CHD. Their data suggest that diabetic patients without a previous MI have a higher risk of MI than nondiabetic patients who have had a previous history of MI. Persons with diabetes have a nearly seven-fold increase in heart disease compared to nondiabetic patients. CHD is the number one cause of death in the developed world, and accounts for over 500,000 deaths per year in the United States alone. It is clear that the emerging diabetic epidemic facing the developing nations of the world will significantly change rates of CHD and associated mortality in coming years.
In the United States alone, the cost of treating uncomplicated diabetes is over 6 billion dollars per year. Acute complications of diabetes, such as emergent hypoglycemia or hyperglycemia, raise that cost significantly. The chronic complications of diabetes, as mentioned above, totaled over 44.1 billion dollars in 1997. That represented 10,071 dollars per each diabetic patient in the United States. The total cost related to diabetic complications in the United States is estimated to be at least 100 billion dollars per year…
Numerous studies have shown that the key to decreasing diabetic complications lies with strict glucose control. The Diabetic Control and Complications Trial (DCCT) has shown the benefits of intensive blood glucose control in patients with type 1 diabetes. Intensive glucose control reduced the risk of developing retinopathy by 54%. Neuropathy was reduced 60% and albuminuria by 54%, respectively. With regards to type 2 diabetes mellitus, the United Kingdom Prospective Diabetes Study (UKPDS) was a randomized clinical trial involving 3867 newly diagnosed patients with type 2 diabetes. After 3 months of diet treatment alone, patients with a mean of two fasting plasma glucose concentrations of 6.1 to 15.0 mmol/L were randomly assigned to either an intensive glycemic control group or a conventional control group. This study showed a 21% reduction in risk for progression of diabetic retinopathy over a 12-year period in the intensive group. In addition, there was a 29% reduction in the need for retinal photocoagulation in the intensive group compared to the conventional group. Overall, there was a 37% reduction in the risk of an adverse microvascular complication with intensive control that was less strict than current guidelines. The UKPDS study also demonstrated that glycemic control appears to diminish with time. Clearly, the best indicator of glycemic control continues to be hemoglobin A1C (HgbA1c). Skyler and associates have demonstrated that HgbA1C levels correlate in a direct relationship with the relative risk of diabetic microvascular complications. Strict glucose control weight control and exercise, remain the essential elements to prevent the complications of diabetic disease.