title: Young men were at risk of becoming lost to follow-up in a cohort of head-injured adults.
abstract: OBJECTIVE
  This study is to identify predictors of loss to follow-up among adults with head injury.
  
  
  METHODS
  A prospective cohort of 1,857 adults enrolled in the Medical Research Council (MRC) CRASH trial known to be alive 2 weeks after head injury. Six-month follow-up was defined as "overdue" if over 6 months late. Patient information collected at enrollment and after 14 days was used to predict overdue follow-up. A random two-thirds of the cohort was analyzed using logistic regression and binary recursive partitioning. The regression model and decision rule derived by recursive partitioning were evaluated using the remaining third.
  
  
  RESULTS
  Overdue follow-up was more likely in patients aged 25-34 years (odds ratio, 1.76; 95% confidence interval [CI]=1.18-2.62), victims of assault (1.63; 1.09-2.45), patients independent after 2 weeks (1.79; 1.18-2.72) and patients for whom postcodes (2.36; 1.65-3.39), telephone numbers (1.82; 1.19-2.79) or general practitioners (1.67; 1.16-2.39) were unknown. Binary recursive partitioning specifically identified males aged younger than 43 years to be at risk.
  
  
  CONCLUSIONS
  Successful follow-up in head-injury studies requires patients' postcodes and telephone numbers to be available. Young men remain at risk of becoming lost to follow-up, presenting a challenge for researchers aiming for complete data.
authors.affiliation: CRASH trials Co-ordinating Centre, Department of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. phil.edwards@LSHTM.ac.uk
authors.forename: Phil
authors.initials: P
authors.lastname: Edwards
authors.forename: Janice
authors.initials: J
authors.lastname: Fernandes
authors.forename: Ian
authors.initials: I
authors.lastname: Roberts
authors.forename: Nathan
authors.initials: N
authors.lastname: Kuppermann
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D006259:Craniocerebral Trauma / Q000453:epidemiology*; D003663:Decision Trees; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010352:Patient Dropouts; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D014754:Violence