If you live with T1D, you have likely heard of the Diabetes Control and Complications Trial (DCCT)1. The DCCT was a major clinical study, conducted from 1983 to 1993, designed to investigate whether intensive glucose control, aimed at maintaining near-normal blood glucose levels, would affect the development and progression of diabetes complications over a period of 10 years.
In this study, 1,441 volunteers (1,246 adults and 195 adolescents) with T1D were randomly assigned to one of two treatment groups:
- The intensive treatment group administered insulin using multiple (3-4) daily injections or an insulin pump. Participants in this group checked their blood glucose levels frequently (at least 3-4 times daily), and made active dose adjustments to keep blood glucose levels as close to a non-diabetic range as possible.
- The conventional treatment group administered 1-2 insulin injections per day and checked urine or blood glucose levels no more than twice daily. At the time, this was the standard treatment for T1D.
The study showed that intensive treatment (compared to conventional treatment) significantly reduced the risk of diabetes complications. Specifically, keeping blood glucose levels as close to a non-diabetic range as possible significantly slowed the development and progression of microvascular (eye, kidney, nerve) complications associated with T1D. The DCCT findings were deemed so “clear and compelling” that the external board of experts monitoring the progress of the DCCT recommended that the study be stopped one year ahead of schedule. In June 1993, study investigators presented these results at the annual scientific meeting of the American Diabetes Association and were given a standing ovation by the more than 10,000 scientists and clinicians in attendance.
When the DCCT ended, the study group felt it was important to continue following participants to examine the long-term effects of the DCCT treatment assignment and current therapy on diabetes complications. More than 90% of the study participants agreed to continue their participation through a follow-up study known as the Epidemiology of Diabetes Intervention and Complications (EDIC)2 study. This study, still active today, focuses on the incidence and predictors of cardiovascular disease events, as well as diabetic complications related to the eye, kidney, and nerves.
Last month, the research team behind the DCCT/EDIC studies published new findings in the Journal of the American Medical Association3 on a cohort of participants who were followed in these studies over a 27-year period. With the opportunity to examine long-term outcomes in this cohort, the investigators observed that when intensive treatment was implemented in the first 15 years following onset, mortality rates were reduced compared to conventional therapy. In addition, all-cause mortality was significantly higher in participants with higher mean HbA1c levels and with renal (kidney) disease during the 20-year follow-up.
The novel finding that kidney disease was actually a predictor of all-cause mortality is consistent with previous work, which has suggested that kidney disease and kidney function loss are among the most serious health problems caused by diabetes4. Importantly, these findings underscore the importance of screening and early treatment of kidney disease in patients with T1D.
On Glu, we recently introduced a study by the Preventing Early Renal Loss (PERL) in Diabetes Consortium, a group of researchers committed to finding better answers for people with T1D and early diabetic kidney complications. Funded by the National Institutes of Health (NIH) and the JDRF, they are conducting a study of a medication called allopurinol to see whether it may help prevent or slow the progression of early kidney disease in people with T1D. This study is still recruiting participants, and we invite you to take the screening questionnaire to see if you qualify for this study.
As the DCCT showed us, a single clinical trial has the potential to significantly change the standard of care for T1D and its complications. Recruitment of study volunteers is critical in order to accelerate the pace of medical research and deliver the next generation of treatments and clinical care. We hope you will continue to provide your valuable insight and experiences by participating in T1D Research.
1 The DCCT Research Group. (1993). The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med, 329 (14), 977-986.
2 The DCCT/EDIC Study Research Group. (2005). Intensive diabetes treatment and cardiovascular disease in patients with type 1 diabetes. N Engl J Med, 353 (25), 2643-2653.
3 Writing Group for the DCCT/EDIC Research Group. (2015). Association between 7 years of intensive treatment of type 1 diabetes and long-term mortality. JAMA, 313 (1), 45-53.
4 American Diabetes Association. (2004). Nephropathy in diabetes. Diabetes Care, 27 (Suppl. 1), S79-S83.