title: Assessing sample representativeness in randomized controlled trials: application to the National Institute of Drug Abuse Clinical Trials Network.
abstract: To compare the characteristics of individuals participating in randomized controlled trials (RCTs) of treatments of substance use disorder (SUD) with individuals receiving treatment in usual care settings, and to provide a summary quantitative measure of differences between characteristics of these two groups of individuals using propensity score methods. Design Analyses using data from RCT samples from the National Institute of Drug Abuse Clinical Trials Network (CTN) and target populations of patients drawn from the Treatment Episodes Data Set-Admissions (TEDS-A). Settings Multiple clinical trial sites and nation-wide usual SUD treatment settings in the United States.
  
  
  
  A total of 3592 individuals from 10 CTN samples and 1 602 226 individuals selected from TEDS-A between 2001 and 2009. Measurements The propensity scores for enrolling in the RCTs were computed based on the following nine observable characteristics: sex, race/ethnicity, age, education, employment status, marital status, admission to treatment through criminal justice, intravenous drug use and the number of prior treatments. Findings The proportion of those with ≥ 12 years of education and the proportion of those who had full-time jobs were significantly higher among RCT samples than among target populations (in seven and nine trials, respectively, at P < 0.001). The pooled difference in the mean propensity scores between the RCTs and the target population was 1.54 standard deviations and was statistically significant at P < 0.001.
  
  
  
  In the United States, individuals recruited into randomized controlled trials of substance use disorder treatments appear to be very different from individuals receiving treatment in usual care settings. Notably, RCT participants tend to have more years of education and a greater likelihood of full-time work compared with people receiving care in usual care settings.
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Susukida
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.|Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.|Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Crum
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stuart
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Cyrus
authors.initials: C
authors.lastname: Ebnesajjad
authors.affiliation: Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.|Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
authors.forename: Ramin
authors.initials: R
authors.lastname: Mojtabai
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D003416:Criminal Law; D004522:Educational Status; D004651:Employment; D005006:Ethnicity; D005260:Female; D006801:Humans; D008297:Male; D017533:Marital Status; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D016032:Randomized Controlled Trials as Topic; D017678:Sex Distribution; D015819:Substance Abuse, Intravenous / Q000453:epidemiology; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000628:therapy*; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Clinical trials; sample representativeness; substance use disorders
references.citation: Addiction. 2009 Feb;104(2):256-65
references.pmid: 19149822
references.citation: J Behav Ther Exp Psychiatry. 2014 Mar;45(1):170-7
references.pmid: 24172145
references.citation: Health Aff (Millwood). 2009 May-Jun;28(3):783-91
references.pmid: 19414887
references.citation: Alcohol Alcohol. 2012 Nov-Dec;47(6):702-10
references.pmid: 22986010
references.citation: Patient Educ Couns. 2010 Jan;78(1):5-11
references.pmid: 19525084
references.citation: BMJ. 2005 Apr 23;330(7497):960-2
references.pmid: 15845982
references.citation: Cultur Divers Ethnic Minor Psychol. 2011 Oct;17(4):345-56
references.pmid: 21988575
references.citation: Cochrane Database Syst Rev. 2010 Apr 14;(4):MR000013
references.pmid: 20393971
references.citation: Arch Gen Psychiatry. 2005 Oct;62(10):1148-56
references.pmid: 16203960
references.citation: Addiction. 2005 Aug;100(8):1090-100
references.pmid: 16042639
references.citation: Alcohol Clin Exp Res. 2003 Aug;27(8):1278-85
references.pmid: 12966322
references.citation: Drug Alcohol Depend. 2005 Sep 1;79(3):311-20
references.pmid: 16102375
references.citation: Am J Psychiatry. 2000 Apr;157(4):588-94
references.pmid: 10739418
references.citation: Drug Alcohol Depend. 2006 Feb 28;81(3):301-12
references.pmid: 16169159
references.citation: Am J Prev Med. 2007 Jun;32(6 Suppl):S203-10
references.pmid: 17543712
references.citation: J Subst Abuse Treat. 2008 Sep;35(2):161-73
references.pmid: 18083322
references.citation: Arch Gen Psychiatry. 2006 Feb;63(2):201-8
references.pmid: 16461864
references.citation: Psychosom Med. 2004 Jan-Feb;66(1):72-8
references.pmid: 14747640
references.citation: Health Technol Assess. 2005 Oct;9(38):iii-iv, ix-x, 1-152
references.pmid: 16181564
references.citation: J R Stat Soc Ser A Stat Soc. 2001 Apr 1;174(2):369-386
references.pmid: 24926156
references.citation: BMJ. 2006 Aug 12;333(7563):346-9
references.pmid: 16902217
references.citation: Clin Toxicol (Phila). 2009 Jan;47(1):48-57
references.pmid: 18787999
references.citation: BMJ. 2009 Jun 29;338:b2393
references.pmid: 19564179
references.citation: BMC Bioinformatics. 2013 Aug 27;14:261
references.pmid: 23981907
references.citation: J Consult Clin Psychol. 2007 Aug;75(4):556-67
references.pmid: 17663610
references.citation: Am J Drug Alcohol Abuse. 2002;28(1):55-72
references.pmid: 11853135
references.citation: Psychol Methods. 2009 Dec;14(4):323-48
references.pmid: 19968396
references.citation: J Res Educ Eff. 2016;9(1):103-127
references.pmid: 27668031
references.citation: Stat Sci. 2010 Feb 1;25(1):1-21
references.pmid: 20871802
references.citation: JAMA. 2008 Nov 5;300(17):2003-11
references.pmid: 18984887
references.citation: Am J Orthopsychiatry. 2005 Jan;75(1):3-18
references.pmid: 15709846
references.citation: Arch Gen Psychiatry. 2011 Dec;68(12):1238-46
references.pmid: 22065255
references.citation: Stat Med. 2010 Feb 10;29(3):337-46
references.pmid: 19960510
references.citation: Drug Alcohol Depend. 2010 Sep 1;111(1-2):177-81
references.pmid: 20537813
references.citation: Alcohol Clin Exp Res. 2007 Jun;31(6):988-95
references.pmid: 17428295
references.citation: J Clin Psychiatry. 2008 Aug;69(8):1276-80
references.pmid: 18557666
references.citation: Am J Psychiatry. 2002 Apr;159(4):620-9
references.pmid: 11925301
references.citation: BMJ. 2003 Sep 6;327(7414):557-60
references.pmid: 12958120