title: Tracking inner city substance users from the emergency department: how many contacts does it take?
abstract: BACKGROUND
  Longitudinal studies of substance users report difficulty in locating and completing 12-month interviews, which may compromise study validity.
  
  
  OBJECTIVE
  This study examined rates and predictors of contact difficulty and in-person follow-up completion among patients presenting with cocaine-related chest pain to an inner-city emergency department (ED). The authors hypothesize that less staff effort in contacting patients and lower follow-up rates would bias subsequent substance use analysis by missing those with heavier substance misuse.
  
  
  METHODS
  A total of 219 patients aged 19 to 60 years (65% males; 78% African American) with cocaine-related chest pain were interviewed in the ED and then in person at 3, 6, and 12 months. Demographics, substance use measures, and amount/type of research staff contacts (telephone, letters, home visits, and locating patient during return ED visits) were recorded. Poisson and negative binomial regression analyses were conducted to predict quantity of patient contacts for the 12-month follow-up.
  
  
  RESULTS
  Interview completion rates at 3, 6, and 12 months were 78, 82, and 80%, respectively. Average contact attempts to obtain each interview were 10 at 3 months (range 3-44), 8 at 6 months (1-31), and 8 at 12 months (1-49); 13% of patients required a home visit to complete the 12-month interview. Participants requiring more contact attempts by staff were younger and reported more frequent binge drinking at baseline (p < 0.05), but were less likely to meet criteria for substance abuse or dependence (p < 0.5), or to report prior mental health treatment (p < 0.05). Comparisons of parallel regressions predicting contact difficulty based on the entire sample, the low-effort group, and the difficult-to-reach group showed variation in findings.
  
  
  CONCLUSIONS
  This study demonstrates that substantial staff effort is required to achieve adequate retention over 12 months of patients with substance misuse. Without these extensive efforts at follow-up, longitudinal analyses may be biased.
authors.affiliation: Department of Emergency Medicine, University of Michigan, Ann Arbor, MI, USA. stroh@umich.edu
authors.forename: Rebecca
authors.initials: R
authors.lastname: Cunningham
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Walton
authors.forename: Shanti P
authors.initials: SP
authors.lastname: Tripathi
authors.forename: Ryan
authors.initials: R
authors.lastname: Outman
authors.forename: Regan
authors.initials: R
authors.lastname: Murray
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Booth
mesh_terms: D000328:Adult; D035843:Biomedical Research / Q000458:organization & administration*; D002637:Chest Pain; D019970:Cocaine-Related Disorders; D004636:Emergency Service, Hospital; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007407:Interviews as Topic; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010352:Patient Dropouts; D016008:Statistical Distributions; D014505:Urban Population