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Examining the Factor Structure of the Clinical Opiate Withdrawal Scale: A Secondary Data Analysis from the National Drug Abuse Treatment Clinical Trials Network (CTN) 0003.

Drug and Alcohol Dependence 2015;152:218-222. [doi: 10.1016/j.drugalcdep.2015.03.036]

Celestina Barbosa-Leiker, PhD, Sterling McPherson, PhD, Mary Rose Mamey, MA, G. Leonard Burns, PhD, Matthew E. Layton, MD, PhD, John M. Roll, PhD (all previous of Washington State University, PN Node), Walter Ling, MD (University of California, Los Angeles, PR Node).

The Clinical Opiate Withdrawal Scale (COWS) is used to assess withdrawal in clinical trials and practice. The aims of this study were to examine the inter-item correlations and factor structure of the COWS in opioid-dependent men and women. This is a secondary data analysis of the National Drug Abuse Treatment Clinical Trials Network study CTN-0003, a randomized clinical trial that compared buprenorphine/naloxone tapering strategies. The trial included 11 sites in 10 US cities. Participants were opioid-dependent individuals (n=516) that had data on the COWS. The COWS at study baseline was analyzed in the study. Inter-item correlations showed weak to moderate relationships between the items. A 1-factor model did not fit the data for men, where resting pulse rate was not related to withdrawal for men, and yawning and gooseflesh skin was not related to withdrawal for women. A reduced model comprised of only the 8 items that were significantly related to the construct of withdrawal in both men and women, and an exploratory 2-factor model, were also assessed but not retained due to inconsistencies across gender.

Conclusions: This study failed to find a single model where all items were related to the construct of withdrawal (i.e., statistically significant meaningful factor loadings) for men and women in mild withdrawal. Further research testing the hypothesized factor structure in other opioid-dependent samples, particularly in samples with greater variation in COWS scores and for those in moderate opioid withdrawal, is needed. The COWS was developed to rate severity within each item because that corresponds with clinical severity within the individual on each item; that may not be necessarily the case across items. The composite score simply acknowledges that some individual will show more, or less, withdrawal symptoms within certain physiological systems and may therefore not assess a single construct of withdrawal. Further research testing the hypothesized factor structure in other opioid-dependent samples is needed. (Article (Peer-Reviewed), PDF, English, 2015)

Keywords: Buprenorphine/Naloxone | CTN platform/ancillary study | Gender differences | Opioid dependence | Psychometrics | Screening and assessment instruments | Taper schedules | Withdrawal syndrome | Women | Drug and Alcohol Dependence (journal)

Document No: 1140, PMID: 25908321, PMCID: PMC4458161.

Submitted by CTN Dissemination Librarians, 5/4/2015.

Barbosa-Leiker, Celestina
Burns, G. Leonard
Layton, Matthew E. mail
Ling, Walter mail
Mamey, Mary Rose search
McPherson, Sterling search mail
Roll, John M. search mail
NIDA-CTN-0003 www

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Supported by a grant from the National Institute on Drug Abuse to the University of Washington Alcohol and Drug Abuse Institute.
The materials on this site have neither been created nor reviewed by NIDA.
Updated 7/2015 --
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