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Demographic and Operational Factors Predicting Study Completion in a Multisite Case-Control Study of Preschool
Chyrise B Bradley1, Erica N Browne1, Aimee A Alexander2
1Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Insights
Participant completion in autism spectrum disorder research varied by maternal factors like age and education, impacting study validity. Strategies must address these differences for future research on autism risk factors.
Area of Science:
- Pediatric Research
- Autism Spectrum Disorder Etiology
- Epidemiological Studies
Background:
- Participant attrition poses a significant challenge to the validity and cost-effectiveness of research studies.
- Understanding factors influencing study completion is crucial for improving data quality and research outcomes.
Purpose of the Study:
- To identify demographic and administrative factors associated with participant completion in a large, multi-component case-control study of autism spectrum disorder (ASD) risk factors.
- To inform strategies for enhancing participant retention in developmental and autism research.
Main Methods:
- A case-control study involving 3,769 preschoolers and their families across multiple US states.
- Mixed-effects logistic regression models were used to analyze factors predicting completion of various study components.
- Completion was defined as participation in phone interviews, questionnaires, in-person evaluations, and biologic sampling.
Main Results:
- Individual study component completion rates exceeded 70%, but only 58% of families completed all per-protocol data elements.
- Maternal age, race, educational level, travel distance, enrollment contact attempts, and provided phone numbers significantly influenced per-protocol completion (P < 0.05).
- Autism spectrum disorder case status did not affect completion rates; household income, primary language, and family structure did not show significant differences in a subset analysis.
Conclusions:
- Participant completion in autism spectrum disorder research is influenced by maternal demographics and logistical factors.
- Differences in completion based on race and education highlight the need for targeted recruitment and retention strategies.
- Future research should proactively address identified factors to minimize attrition and enhance the reliability of autism spectrum disorder risk factor studies.
Abstract:
Participant attrition can limit inferences drawn from study results and inflate research costs. We examined factors associated with completion of the Study to Explore Early Development (2007-2011), a multiple-component, case-control study of risk factors for autism spectrum disorder in preschoolers, conducted in California, Colorado, Georgia, Maryland, North Carolina, and Pennsylvania. Participants (n = 3,769) were asked to complete phone interviews, questionnaires, an in-person evaluation, and biologic sampling. We examined whether participant demographic and administrative factors predicted completion using mixed-effects logistic regression models. Completion of individual key study components was generally 70% or higher. However, 58% of families completed all per-protocol data elements (defined a priori as key study components). Per-protocol completion differed according to mother's age, race, educational level, driving distance to clinic, number of contact attempts to enroll, and number of telephone numbers provided (all P < 0.05). Case status was not associated with completion, despite additional data collection for case-confirmation. Analysis of a subset that completed an early interview revealed no differences in completion by household factors of income, primary language spoken, number of adults, or number of children with chronic conditions. Differences in completion by race and education were notable and need to be carefully considered in developing future recruitment and completion strategies.
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