The researchers, from the Diabetes Control and Complications Trial (DCCT), funded by the NIH (National Institutes of Health), and its long-term follow-up study, EDIC (Epidemiology of Diabetes Interventions and Complications), gave an overview of the findings of this landmark study, three decades after it was launched.
The DCCT started in 1983. It showed that compared to conventional therapy, intensive therapy was much more effective at achieving near-normal blood sugar levels as well as minimizing the risk of complications. Achieving good blood glucose control was made possible through:
- Insulin pump therapy
- (or) Frequent insulin injections
- Self-monitoring of blood glucose levels with fingerstick testing several times a day
Study co-chair, David M. Nathan, MD, director of the Massachusetts General Hospital Diabetes Center in Boston, said:
"On the basis of these results, DCCT intensive therapy has been adopted worldwide as the standard of therapy for type 1 diabetes."
While it was clear that the results of DCCT were "dramatic", there were no accurate measurements for reductions in the long-term consequences of type 1 diabetes-related complications, including blindness, renal failure, heart disease and amputations.
In order to answer these questions, the researchers conducted a long-term follow up of the DCCT over the last two decades. At least 95% of the original 1,441 DCCT participants have been monitored regularly.
Below are some of the follow-up data presented by the DCCT-EDIC researchers:
- Kidney Disease
Long-term type 1 diabetes intensive therapy reduced the risk of developing impaired kidney function by 50%.
Ian deBoer, MD, from the University of Washington, Seattle, a DCCT/EDIC researcher, said "The reduction in impaired kidney function represents a major finding since kidney failure increases the risk of subsequent heart disease and death more than any other complications."
- Stroke and Heart Disease
Type 1 diabetes patients on long-term intensive therapy had an almost 60% lower risk of stroke and heart disease.
According to John Lachin, MD, principal researcher for the DCCT/EDIC Coordinating Center at The George Washington University, Washington D.C., said "The reductions in heart attacks and strokes should translate over time into reduced early death."
Cardiovascular disease is the main cause of premature death in diabetes. Heart disease and stroke are examples of cardiovascular disease.
- Eye Disease
Intensive long-term therapy reduced the risk of severe, vision-threatening stages of diabetic eye disease by 50%. There was also a substantial reduction in the risk of patients needing eye surgery and procedures.
Lloyd Aiello, MD, from the Joslin Diabetes Center in Lanham, Md., who is also a DCCT/EDIC researcher, said "Although we have means of treating severe eye disease to prevent vision loss, it is always better to reduce its development in the first place in order to avoid the need for expensive and only partly effective late-stage therapies. Intensive diabetes therapy effectively accomplishes this goal."
Stiffening around the Hands and ShouldersTwo-thirds of type 1 diabetes patients are susceptible to stiffening around the hands and shoulders, which in many cases can undermine their ability to carry out everyday tasks. This is a commonly under-appreciated complication of diabetes, compared to eye, kidney and cardiovascular issues.
The DCCT/EDIC researchers reported on the problem of hand and shoulder flexibility.
Mary Larkin, RN, a DCCT/EDIC researcher at Massachusetts General Hospital, Boston, said "Lower glucose level was associated with reduced risk of these complications as it is for the other better recognized complications."
Intensive therapy should be implemented as soon as the type 1 diabetes patient is diagnosed, the researchers emphasized. Even though it requires a great deal of effort, represents higher costs, and raises the risk for hypoglycemia, long-term intensive therapy really does eventually pay off.
Dr Nathan said "The DCCT/EDIC has given new hope to people with type 1 diabetes."
Judith Fradkin, MD, director of the Division of Diabetes, Endocrinology and Metabolic Diseases of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), said:
"The long-term results of the DCCT/EDIC further reinforce the importance of early intensive therapy over the lifetime of people with type 1 diabetes. Our challenge now is to ensure that all patients with type 1 diabetes are able to take advantage of these remarkable findings and to make intensive therapy as convenient and safe as possible."
Researchers from Sun Yat-Sen University, Guangzhou, China, reported in The Lancet (May 2008 issue) that early intensive insulin therapy helps type 2 diabetes patients improve the function of their insulin-producing β-cells.