Diabetes Control and Complications Trial and follow-up study

The Diabetes Control and Complications Trial (DCCT) was a 10-year study of people with type 1 diabetes. The study looked at whether people with type 1 diabetes treated in the standard way had more or fewer complications from diabetes than people using tightly controlled therapy.¹

Standard therapy

The people using standard therapy:

• Injected insulin once or twice daily.
• Checked their blood sugar levels daily.
• Visited a doctor, a diabetes nurse educator, and/or dietitian at least 4 times per year.

Tightly controlled therapy

The people using tightly controlled therapy:

• Injected short-acting insulin 3 or more times daily or used an insulin pump.
• Checked their blood sugar levels 4 times a day.
• Had monthly visits with a doctor, diabetes nurse educator, and a dietitian.

By the end of the study, the group using tightly controlled therapy had 76% fewer incidences of eye disease, 54% fewer incidences of kidney disease, and 60% fewer incidences of nerve damage than the group using standard therapy. However, the people who tightly controlled blood sugar had more episodes of low blood sugar and gained more weight than those in the other group.²

The follow-up 12-year study (Epidemiology of Diabetes Interventions and Complications, or EDIC) looked at whether tight control can decrease the heart and blood vessel diseases (macrovascular disease) related to diabetes. People who took part in the DCCT were invited to participate in this study. The researchers compared tightly controlled blood sugar with conventional blood sugar control. They found that tightly controlled blood sugar:

• Lowered the risk of heart disease events, like heart attacks, by 40%.¹
• Lowered the risk of death from heart disease by about 60%.¹
• Slowed the progress of eye disease (diabetic retinopathy) and kidney disease (diabetic nephropathy) by 35% to 90%.³

Citations

1. Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study Research Group (2005). Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes. New England Journal of Medicine, 353(25): 2634–2653.

2. Diabetes Control and Complications Trial Research Group (1996). Lifetime benefits and costs of intensive therapy as practiced in the Diabetes Control and Complications Trial. JAMA, 276(17): 1409–1415.

3. Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Research Group (2002). Effect of intensive therapy on the microvascular complications of type 1 diabetes mellitus. JAMA, 287(19): 2563–2569.