SOME QUESTIONS AND ANSWERS

What medicines are used to treat diabetes?

Type 1 diabetes is managed through the use of self-injected insulin to control blood glucose, as well as through education about aspects of diet, lifestyle and exercise.

Type 2 diabetes is initially managed by education on diet and exercise, but in many people satisfactory control of blood glucose is only achieved through the use of medication as well.

Where diet and exercise interventions are not sufficient to control blood glucose and the individual is overweight, the oral biguanide metformin will usually be tried first, if kidney function is normal. In those who are not overweight, or who are not considered suitable for metformin, a sulphonylurea, which stimulates insulin secretion, is normally used instead.

Acarbose, which decreases carbohydrate absorption, may be used in people inadequately controlled on diet alone or on diet and other oral blood glucose lowering agents.

If blood glucose control is inadequate with a single medicine, combinations of oral medicines can be prescribed. Additional classes of oral medicines that may be used include meglitinide analogues, which increase insulin secretion, and glitazones, which reduce insulin resistance and improve beta-cell function. Glitazones may also be used as single therapy instead of metformin.

If combinations of oral medicines are insufficient to control blood glucose, insulin treatment may be necessary, often together with an oral medicine.

In addition, many people with diabetes require medicines to control blood pressure or regulate blood fats and cholesterol. These are mentioned later, but are not discussed in detail in this booklet.

What are the possible long-term complications of diabetes?

In both type 1 and type 2 diabetes, good control of blood glucose through diet, exercise and medication, and of other risk factors such as hypertension, can prevent complications from developing, even after several decades. This has been demonstrated in a number of large clinical studies, of which perhaps the best known is the United Kingdom Prospective Diabetes Study (UKPDS), which followed 5,000 people with type 2 diabetes for 20 years.

Unfortunately, even people whose diabetes is initially well controlled may go on to develop problems, especially after many years of living with diabetes, as hyperglycaemia tends to worsen over time. This most often causes damage to the cells lining the blood vessels, certain cells in the kidney, and peripheral nerve cells.

Damage to small blood vessels is termed microvascular disease. In the retina of the eye, it gives rise to sight-impairing damage (retinopathy). Damage in the kidneys, which affects their filtering ability, is known as nephropathy. Damage to peripheral nerves ( neuropathy) results in chronic pain or loss of sensation.

Damage to the cells lining the large blood vessels is known as macrovascular disease, and can give rise to heart attacks and strokes as well as circulatory problems (peripheral vascular disease).

Another common complication of diabetes in men is erectile dysfunction, affecting about 60 per cent of men with diabetes over the age of 60. This may be the result of both nerve damage and damage to blood vessels, but certain medications needed by such patients can also be a contributory factor.

In an audit of more than 10,000 patients with diabetes in Wales, coronary heart disease was the most common complication to develop in people with diabetes. Fifty-two per cent of the patients had no complications, but 25 per cent had coronary heart disease and over 16 per cent had retinopathy. Nearly 18 per cent of the patients had two or more complications.

Another survey, this time on Tayside in Scotland, has provided data on the annual incidence rates of various complications in both type 1 and type 2 diabetes.

Diabetic complications - Incidence/year/1,000 persons Complication Type 1 diabetes Type 2 diabetes Angina 8.8 38.4 Heart attack 8.6 21.9 Stroke 1.1 14.2 Amputation* 3.2 3.1 PVD 5.5 13.6 Blindness 1.1 1.6 ESRD 6.4 5.0 Deaths 14.6 50.0

PVD Peripheral Vascular Disease ESRD End Stage Renal Disease, * lower-limb amputation

The incidence of complications was generally higher in those with type 2 diabetes, perhaps reflecting the longer exposure to hyperglycaemia before they were diagnosed.