Appendix 1: Diabetes complications

The free annual check for people with diabetes aims to ensure that regular tests are carried out to identify and treat complications at an early stage and to agree individual treatment plans for patients. The types of complications being tested for and the types of treatment are set out below.

Kidneys and heart

In New Zealand, diabetes is the most common cause of kidney failure.

About 40% of people with type 1 diabetes and 5% to 10% of people with type 2 diabetes will develop progressive kidney failure. The prevalence of kidney disease and kidney failure is higher among Māori and Pacific Island peoples than among people of European origin.

Cardiovascular disease is the leading cause of death in people with diabetes. The presence of diabetes increases the risks of coronary artery disease two to three times in men, and four to five times in women, when compared to people without diabetes.

Controlling blood pressure through the use of ACE inhibitors or other medication to reduce the risk of developing both cardiovascular and kidney complications is very important for people with diabetes.

People with diabetes also need to monitor cholesterol, and they may need statins or other medication to reduce the level of cholesterol in the blood.

Eyes

Diabetes is the most common cause of avoidable loss of vision in people of working age in developed countries. International studies suggest that about 70 people in New Zealand become legally blind every year as a result of diabetes. The most significant effects of diabetes on vision are on the retina and the retinal blood vessels, a condition known as diabetic retinopathy. After 10 years with diabetes, about 40% to 50% of people will develop complications with their vision.

The effect of diabetes on the eyes is much more widespread in Māori and Pacific Island peoples.

Diabetic retinopathy can be detected reliably by screening programmes. It generally takes three years before loss of vision. New Zealand’s best practice guidelines for diabetes treatment recommend retinal screening every two years.

Laser treatment is often used to treat diabetic retinopathy successfully at an early stage.

Nerves

The longer a person has diabetes, the greater the risk they have of developing damage to the nerves around the body. This is referred to as neuropathy. It can cause loss of sensation in the toes, feet, lower and upper legs, and the hands and arms. This can easily develop into ulcers, which can lead to amputation when poorly treated. About 15% of people with diabetes will have foot ulcers at some time in their life that will need specialised podiatry.

Nerve damage can also occur in other parts of the body and affect the functioning of the bowel and the bladder, digestion, perspiration, and sexual response.

Maintaining good glucose control to reduce the risk of getting nerve damage is important. Incidences of nerve damage are more common in patients with higher than normal blood glucose levels often with an HbA1c over 10%, who are overweight, who have higher levels of blood fat and blood pressure, and who are over the age of 40.