Diabetes, and the hyperglycemia it causes, has the potential to affect many different systems and organs — the circulatory system, the eyes, the kidneys, the nerves, even the skin and teeth. This is what makes diabetes such a potentially dangerous disease. But developing these complications is not inevitable. One of the most important things for anyone with diabetes to know about complications is that they often can be prevented or delayed. If you have diabetes, it is within your power to minimize your risk of complications.
Diabetes specialists have suspected for a long time that keeping good control of blood glucose levels could prevent complications. This was proven conclusively by a large research project called the Diabetes Control and Complications Trial. Over an average of 6.5 years, the National Institute of Diabetes and Digestive and Kidney Diseases sponsored a study that followed more than 1,400 people with diabetes, comparing how many developed complications in two groups — those using standard therapy and those using intensive therapy. Intensive therapy meant more frequent insulin shots and monitoring, and consequently tighter blood glucose control. The DCCT found the following in the intensive control group:
- 76 percent reduced risk of eye disease
- 50 percent reduced risk of kidney disease
- 60 percent reduced risk of nerve disease
Complications of diabetes can be divided into three categories: short-term or acute, intermediate-term and long-term or chronic.
Acute complications come on quickly, within minutes or hours, and are directly attributable to the current level of blood glucose — either too high or too low. Usually these complications, if treated quickly, are completely reversible. Acute complications include:
- Diabetic ketoacidosis
- Hyperosmolar nonketotic coma
Some people with diabetes, particularly type 1 diabetes, develop intermediate-term problems. One example is slow growth in children. With improved glucose control, growth can move back toward the normal curve.
In general, chronic complications of diabetes are caused by too much glucose in the cells. While glucose cannot enter most cells without insulin to transport it, exceptions are cells in the brain, eyes, kidneys and red blood cells. This is why long-term complications of diabetes are seen most often in the eyes, nerves and kidneys.
Chronic complications develop over years or decades of living with diabetes. We know, however, from the DCCT results in type 1 diabetes and from a United Kingdom study of type 2 diabetes, that careful and attentive management of blood can prevent or delay these long-term complications. Potential long-term complications include:
- Diabetic eye disease (retinopathy)
- Nephropathy (kidney disease)
- Peripheral neuropathy
- Autonomic neuropathy
- Coronary heart disease
- Cerebrovascular disease
- Peripheral vascular disease