The Diabetes Control & Complications Trial (DCCT) ended after 10 years in 1993—a year earlier than planned—when the study proved that participants who kept their blood glucose levels close to normal greatly lowered their chances of having eye, kidney, and nerve disease.
The DCCT showed that people who used intensive treatment lowered their risk of diabetic eye disease by 76 percent and advancement of eye disease by about half (54 percent), in people with some eye disease at the beginning of the study. Intensive treatment also lowered diabetic kidney disease by 50 percent and diabetic nerve disease by 60 percent.
Researchers were not able to show whether people who used intensive treatment lowered their risk of heart disease during the DCCT, since only a few people had heart disease during the study.
Epidemiology of Diabetes Interventions and Complications (EDIC) study has continued to follow DCCT participants for the last 20-plus years.