Participant characteristics and study features associated with high retention rates in a longitudinal investigation of type 1 diabetes mellitus
ABSTRACT BACKGROUND: The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) Study has sustained an extraordinarily high level of participant involvement for over two decades. PURPOSE: In order to identify specific characteristics of EDIC that contributed most strongly to retention, study-designed questionnaires were distributed to 1334 participants. METHODS: Confidential questionnaires were completed during EDIC Years 15-17. Participants were classified as Completely Adherent (completed all visits), Partly Adherent (missed >1 visit or major portion of a visit), or Inactive (did not participate for >5 years). Questionnaire items addressed specific aspects of clinic visits, evaluation procedures, staff-participant relationships, and medical/health-care support provided by EDIC. RESULTS: The most commonly cited reasons for continuing participation were Cutting Edge Tests to assess diabetes complications (79.3%), Annual Evaluations (67.7%), a desire to Help Others (65.2%), and Better Care for Diabetes (61.6%). Women chose Cutting Edge Tests as their first or second most important reason significantly more often than men, whereas men chose Better Care for Diabetes more frequently. Individuals with at least three diabetes-related complications were more likely than those with fewer complications to choose Annual Evaluations as their first or second reason for continued involvement. LIMITATIONS: The small proportion of individuals who discontinued participation restricted our ability to identify factors associated with suspended involvement. In addition, our analysis is limited to a cohort with type 1 diabetes followed in an observational study after an average participation time of 6.5 years in a randomized trial. CONCLUSIONS: The primary reasons identified by respondents for their long-term commitment are consistent with shorter-term studies and underscore the importance of expert medical care, supportive staff-participant relationships, and involvement with clinically and scientifically meaningful research. Clinical Trials 2012; 0: 1-8. http://ctj.sagepub.com.
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ABSTRACT: The role of the study coordinator (SC) in multicenter studies of long duration has received limited attention. To describe the evolution of the SC's role during the 28-year Diabetes Control and Complications Trial (DCCT) and its follow-up study, the Epidemiology of Diabetes Interventions and Complications (EDIC) study. The evolution of the SC's position from the traditional role of protocol implementation to that of research collaborator and co-investigator, based on personal experience and observation, is described in detail. Findings from a survey regarding professional demographics and job satisfaction, completed by all 28 SCs in 2010, provided additional information. We used dimensions of the SC's role specific to DCCT/EDIC to construct a classification schema of functions and responsibilities that describe the SC's role. Among the 28 SCs, 24 were nurses, 12 held bachelor's degrees, 11 had a master's degree, 19 were certified diabetes educators (CDEs), 12 had worked with DCCT/EDIC for more than 20 years, and 5 had been with the study since its inception (>26 years). Responses confirmed a high degree of functional consistency across sites with data acquisition, performing study procedures, recruitment and consent for additional ancillary studies, regulatory management, scheduling, clinical consultation, and ongoing contact with study participants frequently reported. Study-wide leadership activities, a category not generally included in the usual SC role, were reported by approximately 30% of the SCs. The level of professional satisfaction was high with two-thirds being very satisfied, one-third moderately to quite satisfied, and none dissatisfied. The limitations include a relatively small sample size, self-reported data, and a single long-term multicenter trial and observational follow-up study on which we based our findings and conclusions. By optimizing their organizational and scientific contributions to the overall research endeavor, SCs in DCCT/EDIC have made major contributions to the unprecedented success of the study and report high job satisfaction. The efforts of the SCs have been integral to the remarkably high participant retention and data completion rates. The DCCT/EDIC experience may serve as a model for the role of the SC in future diabetes and other multicenter clinical trials.Clinical Trials 06/2012; 9(4):418-25. DOI:10.1177/1740774512449532 · 1.94 Impact Factor
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ABSTRACT: Intensive diabetes therapy reduces the prevalence of coronary calcification and progression of atherosclerosis, and the risk of cardiovascular disease events in the DCCT/EDIC study. The effects of intensive therapy on measures of cardiac function and structure and their association with glycemia have not been explored in type 1 diabetes (T1DM). We assess whether intensive treatment compared to conventional treatment during the DCCT led to differences in these parameters during EDIC. After 6.5 years of intensive versus conventional therapy in the DCCT, and 15 years additional follow-up in EDIC, left ventricular indices were measured by cardiac magnetic resonance (CMR) imaging in 1017 of the 1371 members of the DCCT cohort. There were no differences between the DCCT intensive versus conventional treatment in end diastolic volume, end systolic volume, stroke volume, cardiac output, left ventricular mass, ejection fraction, LV mass/EDV, nor aortic distensibility. Mean DCCT/EDIC HbA1c over time was associated with EDV, SV, CO, LVmass, LVmass/EDV, and AD. These associations persisted after adjustment for CVD risk factors. Cardiac function and remodeling in T1DM assessed by CMR in the EDIC cohort was associated with prior glycemic exposure, but there was no effect of intensive versus conventional treatment during the DCCT on cardiac parameters.Diabetes 03/2013; 62(10). DOI:10.2337/db12-0546 · 8.47 Impact Factor
- Diabetes 12/2013; 62(12):3963-3967. DOI:10.2337/db13-1108 · 8.47 Impact Factor