title: Predictors of follow-up completeness in longitudinal research on traumatic brain injury: findings from the National Institute on Disability and Rehabilitation Research traumatic brain injury model systems program.
abstract: OBJECTIVE
  To identify baseline participant variables in the domains of demographics, medical/psychosocial history, injury characteristics, and postinjury functional status associated with longitudinal follow-up completeness in persons with traumatic brain injury (TBI) using the TBI Model Systems (TBIMS) National Database (NDB).
  
  
  METHODS
  Exhaustive chi-square automatic interaction detection was used to identify factors that classified participants according to level of follow-up completeness.
  
  
  METHODS
  Retrospective analysis of a multi-center longitudinal database.
  
  
  METHODS
  Individuals (N=8249) enrolled in the TBIMS NDB between 1989 and 2009 who were eligible for at least the first (year 1) follow-up up to the fifth (year 15) follow-up.
  
  
  METHODS
  None.
  
  
  METHODS
  Follow-up completeness as defined by 6 different longitudinal response patterns (LRPs): completing all follow-ups, wave nonresponse, dropping out, completing no follow-ups without formally withdrawing, formally withdrawing before completing any follow-ups, and formally withdrawing after completing some follow-ups.
  
  
  RESULTS
  Completing all follow-ups was associated with higher levels of education, living with parents or others, and having acute care payer data entered in the NDB. Subgroups more vulnerable to loss to follow-up (LTFU) included those with less education, racial/ethnic minority backgrounds, those with better motor functioning on rehabilitation discharge, and those for whom baseline data on education, employment, and acute care payer were not collected. No subgroups were found to be more likely to have the LRPs of dropping out or formal withdrawal.
  
  
  CONCLUSIONS
  These data identify subgroups in which retention strategies beyond those most commonly used might reduce LTFU in longitudinal studies of persons with TBI, such as the TBIMS, and suggest future investigations into factors associated with missing baseline data.
authors.affiliation: Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY. Electronic address: jason.krellman@mountsinai.org.
authors.forename: Jason W
authors.initials: JW
authors.lastname: Krellman
authors.affiliation: Santa Clara Valley Medical Center, Rehabilitation Research Center, San Jose, CA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Kolakowsky-Hayner
authors.affiliation: Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY.
authors.forename: Lisa
authors.initials: L
authors.lastname: Spielman
authors.affiliation: Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY.
authors.forename: Marcel
authors.initials: M
authors.lastname: Dijkers
authors.affiliation: Indiana University School of Medicine, Indianapolis, IN.
authors.forename: Flora M
authors.initials: FM
authors.lastname: Hammond
authors.affiliation: Department of Physical Medicine and Rehabilitation, Ohio State University, Columbus, OH.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bogner
authors.affiliation: Moss Rehabilitation Research Institute, Elkins Park, PA.
authors.forename: Tessa
authors.initials: T
authors.lastname: Hart
authors.affiliation: Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY.
authors.forename: Joshua B
authors.initials: JB
authors.lastname: Cantor
authors.affiliation: Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY.
authors.forename: Theodore
authors.initials: T
authors.lastname: Tsaousides
mesh_terms: D001930:Brain Injuries / Q000453:epidemiology*; D003625:Data Collection / Q000706:statistics & numerical data*; D016208:Databases, Factual; D003663:Decision Trees; D004185:Disability Evaluation; D004522:Educational Status; D006801:Humans; D008137:Longitudinal Studies; D059012:Lost to Follow-Up; D008913:Minority Groups / Q000706:statistics & numerical data; D009316:National Institutes of Health (U.S.); D010352:Patient Dropouts / Q000706:statistics & numerical data; D012111:Residence Characteristics; D012189:Retrospective Studies; D014481:United States
keywords: Bias (epidemiology); Brain injuries; Follow-up studies; Lost to follow-up; Outcome assessment (health care); Rehabilitation