Understanding loss to follow-up in a longitudinal study of people with traumatic brain injury

ABSTRACT

Objective

To examine factors related to attrition in a traumatic brain injury (TBI) study sample assessed up to 15 years after injury.

Participants

One thousand twenty-eight participants with TBI who completed the year 1 follow-up assessment at a TBI Model Systems Center between 1992 and 2018.

Method

Secondary analysis of data from a prospective longitudinal cohort study considering follow-up data collection completion status at years 1, 2, 5, 10, and 15.

Results

In univariable analyses, multiple factors were associated with loss to follow-up (LOFU) including being a member of a socially disadvantaged group, substance use history, residence, payor, cause of injury, and results of earlier follow-up attempts. In a multiple logistic regression analysis examining the prediction of follow-up condition at 10 or 15 years post-injury, only payor and race/ethnicity were significant predictors. Hispanic ethnicity was associated with higher odds of LOFU, and these participants often spoke Spanish and were born outside of the United States.

Conclusions

The findings suggest a need to understand sociodemographic variables and their influence on participant attrition in longitudinal TBI research. With a better understanding of these predictors, procedures can be developed to address retention of participants who are identified as being at increased risk for study drop out.

KEYWORDS:

• Traumatic brain injury
• longitudinal study
• attrition
• lost to follow-up

Conflicts of interest

The authors declare no conflicts of interest.

Additional information

Funding

Preparation of this manuscript was partially supported by National Institute of Disability, Independent Living, and Rehabilitation Research grant # 90DPTB0016. NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of this publication do not necessarily represent the policy of NIDILRR, ACL, or HHS, and you should not assume endorsement by the Federal Government.