It has been 30 years since today’s standard of care was introduced….
The Diabetes Control and Complications Trial (DCCT) was a breakthrough in diabetes research some 30 years ago. The standard of care we know today was considered a new and debated intensive therapy then. This study and its follow up, Epidemiology of Diabetes Interventions and Complications (EDIC), have shaped the development of diabetes care we have today. In light of this "anniversary" this article looks back at all of the advancements made and the long term outcomes that have been assessed and improved. Diabetes has evolved from a fatal disease to a chronic condition but while many contributions have been made since the introduction of insulin in 1922, there are still many obstacles to overcome for optimal diabetes management.
Before the DCCT, there was considerable debate on the value of controlling glucose levels in diabetic patients. This was the "glucose hypothesis" and it was largely theoretical. There was no actual data from clinical studies because self-monitoring didn’t really exist before the 70’s. In the early 80’s the National Diabetes Mellitus Research and Education Act suggested a clinical trial to test the glucose hypothesis. The trial would assess whether glucose levels played a role in prevention of micro/macrovascular complications and whether or not progression could be prevented. By 1983 the trial was underway and the conventional therapy was tested against the new intensive therapy plan. Conventional therapy was intended to avoid the symptoms of hyperglycemia with 1-2 daily insulin injections, a daily glucose test, and education. Intensive therapy included the same goals as conventional therapy but added multiple daily insulin injections, 4 or more glucose tests, meal size and content, exercise and glycemic targets.
The major findings of the DCCT are basically what we know today. The glucose debate was settled: glycemic control is critical in diabetes care. HbA1c levels had dropped significantly in the intensive group by 3-6 months. Researchers found that intensive therapy was "consistent, significant, and clinically meaningful" in the prevention and progression of retinopathy, nephropathy, and neuropathy. Intensive therapy also delayed the reduction of c-peptide by about 50%. The EDIC study followed the previous cohort a little longer to determine the long-term effects of intensive therapy on more advanced diabetes and cardiovascular disease. After 18 years, intensive therapy was shown to reduce the risk of CVD in diabetics. Stroke and MI risk was reduced by nearly 58%.
After this data was released, intensive therapy became accepted worldwide. Recent research in 2012 showed that out of 22,502 T1DM patients over 26yo, the mean HbA1c was 7.6%. Other new research shows that despite all the advancements only 20-25% of teens and 20-35% of adults achieved the American Diabetes Association goal of 7.5% and 7%, respectively. The future of diabetes involves overcoming lack of social support, economic constraints, limited access to healthcare, advancements in technology, education, awareness, and simplification of daily management.
- Studies conducted in the last 30 years show that intensive diabetes management substantially and consistently reduces the occurrence and progression of diabetes and its complications.
- There was a 70% reduction in the risk of further reduction of retinopathy from the end of the DCCT trial.
- The durable effect of the earlier separation in glycemia during DCCT on microvascular complications during the later EDIC is referred to as metabolic memory and the long term benefit continues today.
Nathan, D. et al. Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study at 30 Years: Advances and Contributions. Diabetes 62(12);3976-3986. December 2013.