title: Sample bias from different recruitment strategies in a randomised controlled trial for alcohol dependence.
abstract: OBJECTIVE
  Participants may be recruited from diverse sources for randomised controlled trials (RCT) of treatments for alcohol dependence. A mixed recruitment strategy might facilitate recruitment and increase generalisability at the expense of introducing systematic selection bias. The current study aims to compare the effects of recruitment method on socio-demographics, baseline illness characteristics, treatment retention and treatment outcome measures.
  
  
  METHODS
  A secondary analysis from a previous 12 week RCT of naltrexone, acamprosate and placebo for alcohol dependence was conducted. Participants (n = 169) were obtained via four channels of recruitment including in-patient and outpatient referral, live media and print media solicitation. Baseline parameters, retention in treatment and treatment outcomes were compared in these groups.
  
  
  RESULTS
  Relative to in-patient subjects, those recruited via live and print media had significantly lower scores on taking steps, less in-patient rehabilitation admissions and less previous abstinence before entering the trial. Subjects recruited via print media had significantly lower scores of alcohol dependence relative to all other modes recruitment. There were no differences between recruitment strategies on treatment retention or compliance. At outcome, no significant effect of recruitment method was detected.
  
  
  CONCLUSIONS
  These results suggest that different recruitment methods may be sourcing subjects with different baseline characteristics of illness. Nonetheless, these differences did not significantly impact on treatment retention or outcome, suggesting that in this population it was appropriate to recruit subjects from mixed sources.
authors.affiliation: Central Clinical School of Medicine, The University of Sydney, Sydney, Australia.
authors.forename: Kirsten C
authors.initials: KC
authors.lastname: Morley
authors.forename: Maree
authors.initials: M
authors.lastname: Teesson
authors.forename: Claudia
authors.initials: C
authors.lastname: Sannibale
authors.forename: Paul S
authors.initials: PS
authors.lastname: Haber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance / Q000706:statistics & numerical data; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D016896:Treatment Outcome