Predicting attrition in a pediatric asthma intervention study.

OBJECTIVES To operationalize a comprehensive description of attrition, including pre-inclusion, dropout, and attrition due to intermittent missing data, and to test a predictive model of attrition using a data set from a randomized controlled intervention in pediatric asthma. METHODS Participants included children, ages 4-12, diagnosed with asthma and their caregivers. Demographic variables and outcome measures of asthma morbidity were examined in 327 families to determine their association with attrition. RESULTS Families who did not complete randomization and the intervention tended to have younger caregivers than did completers. Caregiver age emerged as the most consistent predictor of pre-inclusion and dropout attrition. There were no significant predictors of attrition due to intermittent missing data. CONCLUSION Younger caregivers may be at particular risk for attrition in pediatric asthma intervention studies and warrant special attention by investigators.