title: Toward empirical identification of a clinically meaningful indicator of treatment outcome: features of candidate indicators and evaluation of sensitivity to treatment effects and relationship to one year follow up cocaine use outcomes.
abstract: BACKGROUND
  Selection of an appropriate indictor of treatment response in clinical trials is complex, particularly for the various illicit drugs of abuse. Most widely used indicators have been selected based on expert group recommendation or convention rather than systematic empirical evaluation. Absence of an evidence-based, clinically meaningful index of treatment outcome hinders cross-study evaluations necessary for progress in addiction treatment science.
  
  
  METHODS
  Fifteen candidate indicators used in multiple clinical trials as well as some proposed recently are identified and discussed in terms of relative strengths and weaknesses (practicality, cost, verifiability, sensitivity to missing data). Using pooled data from five randomized controlled trials of cocaine dependence (N=434), the indicators were compared in terms of sensitivity to the effects of treatment and relationship to cocaine use and general functioning during follow-up.
  
  
  RESULTS
  Commonly used outcome measures (percent negative urine screens; percent days of abstinence) performed relatively well in that they were sensitive to the effects of the therapies evaluated. Others, including complete abstinence and reduction in frequency of use, were less sensitive to effects of specific therapies and were very weakly related to cocaine use or functioning during follow-up. Indicators more strongly related to cocaine use during follow-up were those that reflected achievement of sustained periods of abstinence, particularly at the end of treatment.
  
  
  CONCLUSIONS
  These analyses did not demonstrate overwhelming superiority of any single indicator, but did identify several that performed particularly poorly. Candidates for elimination included retention, complete abstinence, and indicators of reduced frequency of cocaine use.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States. Electronic address: kathleen.carroll@yale.edu.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Carroll
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Kiluk
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States.
authors.forename: Charla
authors.initials: C
authors.lastname: Nich
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States.
authors.forename: Elise E
authors.initials: EE
authors.lastname: DeVito
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States; New England Mental Illness, Research Education and Clinical Center, VA Connecticut Healthcare System, United States.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Decker
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States.
authors.forename: Donna
authors.initials: D
authors.lastname: LaPaglia
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States.
authors.forename: Dianne
authors.initials: D
authors.lastname: Duffey
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States.
authors.forename: Theresa A
authors.initials: TA
authors.lastname: Babuscio
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, 950 Campbell Avenue, 151D, West Haven, CT 06516, United States; The APT Foundation, New Haven Connecticut, 1 Long Wharf, New Haven, CT 06511, United States.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Ball
mesh_terms: D000818:Animals; D002986:Clinical Trials as Topic / Q000592:standards*; D019970:Cocaine-Related Disorders / Q000175:diagnosis* / Q000453:epidemiology / Q000628:therapy*; D036262:Empirical Research; D005500:Follow-Up Studies; D006801:Humans; D019984:Quality Indicators, Health Care / Q000592:standards*; D016896:Treatment Outcome
keywords: Cocaine use disorders; Follow-up studies; Randomized trials; Treatment outcome indicators