The diabetes control and complications trial/epidemiology of diabetes interventions and complications study at 30 years: summary and future directions

Abstract

OBJECTIVE The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study continues to address knowledge gaps in our understanding of type 1 diabetes and the effects of intensive therapy on its long-term complications. RESEARCH DESIGN AND METHODS During the DCCT (1982-1993), a controlled clinical trial of 1,441 subjects with type 1 diabetes, and the EDIC (1994-present), an observational study of the DCCT cohort, core data collection has included medical history questionnaires, surveillance health exams, and frequent laboratory and other evaluations for microvascular and macrovascular disease. Numerous collaborations have expanded the outcome data with more detailed investigations of cardiovascular disease, cognitive function, neuropathy, genetics, and potential biological pathways involved in the development of complications. RESULTS The longitudinal follow-up of the DCCT/EDIC cohort provides the opportunity to continue monitoring the durability of intensive treatment as well as to address lingering questions in type 1 diabetes research. Future planned analyses will address the onset and progression of microvascular triopathy, evidence-based screening for retinopathy and nephropathy, effects of glycemic variability and nonglycemic risk factors on outcomes, long-term impact of intensive therapy on cognitive decline, and health economics. Three new proposed investigations include an examination of residual C-peptide secretion and its impact, prevalence of hearing impairment, and evaluation of gastrointestinal dysfunction. CONCLUSIONS With the comprehensive data collection and the remarkable participant retention over 30 years, the DCCT/EDIC continues as an irreplaceable resource for understanding type 1 diabetes and its long-term complications.

Figure 1

The DCCT/EDIC core investigations have been the center of a diverse array of supplemental studies and collaborations over the past 30 years. The black circle denotes the major outcomes (i.e., retinopathy, nephropathy, neuropathy, and cardiovascular disease) studied during the DCCT (1983–1993) and throughout EDIC (1994–present). Extending from these core investigations, a multitude of supplemental studies have been performed, starting from 1990–2005, the late DCCT/early EDIC period; continuing with 2006–2013, the first EDIC extension period; and expanding to 2013–forward, the current extension of EDIC. Family genetics study, first-degree relative genetic studies (12); CVD-CAC, coronary calcium CT scan (13); CVD-NMR lipid, lipid studies (14); URO-EDIC 1, study of urological dysfunction (15); CVD-IMT, carotid ultrasounds (–18); AGEs, advanced glycation end products (19); cognitive function, neurocognition testing (–22); CAN, cardiac autonomic neuropathy testing (23); cardiac MRI, enhanced cardiac MRI (11); dermal AGEs, dermal advanced glycation end product study (24,25); retention, participant retention study (26); glycated albumin measurements (27,28); haptoglobin levels (29); cardiovascular biomarkers; epigenetics; mobility, joint mobility; and URO-EDIC 2, repeat study of urological dysfunction.