Factors influencing attrition in a multisite, randomized, clinical trial following traumatic brain injury in adolescence.

Background: Attrition in longitudinal research negatively affects statistical power, disrupts statistical stability, and can produce unwanted bias.

Objective: To investigate factors associated with shorter length of study participation and lower rates of study completion (ie, attrition) in a large, multisite, longitudinal, randomized, clinical trial examining the efficacy of a Web-based family problem-solving treatment following traumatic brain injury (TBI) in adolescence.

Setting: Five major trauma centers in the central and western regions of the United States.

Participants: Children (N = 132) aged 12 to 17 years hospitalized for complicated mild to severe TBI within the previous 6 months.

Results: Completers had a higher primary caregiver education and higher family income than noncompleters, whereas ethnicity, latency to baseline assessment, and intervention group were not significantly associated with study completion.

Conclusion: This is the first study that has specifically examined factors of attrition in a pediatric TBI population. The results suggest that research on pediatric TBI populations may be biased toward higher-income families and highlights the importance of designing studies with increased awareness of the impact of participant demographic factors.