Managing Diabetes

The Diabetes Control and Complications Trial (DCCT)

What is the DCCT?

The Diabetes Control and Complications study or DCCT was a large study into the benefit of tight blood sugar control in people with type 1 diabetes. This was the first big study to show that good control of blood sugar levels, slowed the onset and delayed the progress of complications such as eye, kidney and nerve disease due to diabetes.

Where was it done?

The DCCT was carried out by the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) in the United States and includes almost 1500 people with type 1 diabetes in the US and Canada.

How was it done?

The study researchers divided volunteers into two groups in order to compare intensive control with standard or usual treatment. The people were allocated into the two groups at random.

What were the conclusions drawn?

The investigators found that the intensely treated group had a significantly reduced risk of diabetic retinopathy (76%), nephropathy (50%) and neuropathy (60%).

What problems were encountered with intensive treatment?

The main problem with intensive treatment was more frequent episodes of hypoglycaemia. The programme involved more frequent blood sugar testing and frequent visits to health professionals and they estimated that more intensive management doubles the cost of looking after diabetes. It was felt that this cost was justified as long-term complications and quality of life was improved in people with diabetes.

How did this change the way we look after type 1 diabetes?

People with type 1 diabetes are now motivated to improve their control. Those who are poorly controlled and do not take steps to improve, are made aware of the risk of complications.


Dr Nishan Wijenaike, Consultant Physician
West Suffolk Hospitals Diabetes Service
October 2002