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Concordance between Self-Report and Urine Drug Screen Data in Adolescent Opioid
Dependent Clinical Trial Participants
M. Nakazawa1, C.E. Wilcox2, M.P. Bogenschutz1,2, G.E. Woody3
1Center
on Alcoholism, Substance Abuse and Addictions (CASAA), University of New Mexico, Albuquerque, NM
2Department of Psychiatry, University of New Mexico, Albuquerque, NM
3Department of Psychiatry, University of Pennsylvania, Philadelphia, PA
INTRODUCTION
RESULTS
Using self report to gather information about drug use can be reasonably
reliable and valid in certain situations, especially where there are no
contingencies for reported use, and where certain measures are taken during
the information gathering process (e.g., Del Boca & Noll, 2000). However,
there are some contexts which make the self report data less useful, due to
inaccuracies (e.g., Del Boca & Noll, 2000; Del Boca & Darkes, 2003;
Hoffmann & Ninonuevo, 1994; Midanik, 1988). The purpose of this study
was to explore overall concordance between urine drug screen results and
self-report in an adolescent and young adult population by doing secondary
analyses of a randomized controlled trial of a 12 week suboxone treatment
versus a 14 day suboxone detoxification in opioid addicted youth ages 15~21
METHODS
Participants and Outcomes
In the study, 152 subjects aged 15-21 seeking treatment for opioid
dependence were randomized to 2 week detoxification with
buprenorphine/naloxone (DETOX; N=78), or 12 weeks
buprenorphine/naloxone (BUP; N=74) with a dose taper beginning in week 9
and ending in week 12, each with weekly individual and group drug
counseling (Woody et al, 2008). Subjects were paid $5 for providing a
weekly urine drug screen and self-report of drug use during the preceding 7
days, and $75 for more extensive assessments at weeks 4, 8 and 12.
When provided, urine samples were tested for morphine/opiates and
oxycodone (Opioids), Cocaine, Cannabis, Benzodiazepines, and
Meth/Amphetamine. For each subject at each time point, urine samples and
self-report of drug use were labeled as either positive, negative, or missing.
Based on these values, three measures of concordance were computed:
Cohen’s κ, and Sensitivity/Specificity of self report.
Pr(a) – Pr(e)
κ=
1 – Pr(e)
where Pr(a) is the relative observed agreement among raters, and Pr(e) is
the hypothetical probability of chance agreement.
Sensitivity = Pr(+Self-Report | +Urine)
Week
Specificity = Pr(-Self-Report | -Urine)
SUMMARY
- Cohen’s κ averaged across 12 weeks was relatively high, exceeding 0.70 in all
drugs except for Benzodiazepines (0.57).
- In some drugs κ fluctuated wildly across weeks: in Benzodiazepines the standard
deviation (SD) was 0.33 with the range of -0.04~1.00; in Meth/Amphetamine
SD was 0.32 with the range of 0.00~1.00.
- In terms of Sensitivity, Benzodiazepines again had the lowest average of 0.56.
The other drugs had the average Sensitivity greater than 0.70.
- Sensitivity fluctuated wildly in Benzodiazepines (SD = 0.33, range = 0.04~1.00) and in Meth/Amphetamine (SD = 0.32, range = 0.00~1.00).
- All drugs had very high Specificity averaged across 12 weeks with the highest of
0.99 in Meth/Amphetamine and the lowest of 0.89 in Cannabis.
- Specificity was more stable than the other measures: the greatest SD was 0.04 in
Cannabis and the lowest of 0.01 in Meth/Amphetamine.
SUMMARY
- In opioids, cannabis, and cocaine, concordance of self-report with urine screen
was acceptably high and stable across weeks. This results may mean that testing
the use of these drugs may not require urine-screens, conserving resources.
- On the other hand, in benzodiazepines and meth/amphetamines concordance of
self-report was lower and very unstable. These results may be due to smaller
numbers of positive cases. For instance, there were only 32 (+Self-Report |
+Urine) cases summed across 12 weeks in benzodiazepines and 24 cases in
Cocaine, whereas in other drugs the number ranged from 103 to 372. There
results may indicate that testing the use of infrequently used drugs may require
multiple measures to improve accuracy and precision of measurement.
REFERENCES
• Del Boca, F. & Noll, J.A. (2000). Truth or consequences: The validity of self-report data in health services
research on addictions. Addiction, 95 (Supplement 3), 347-360.
• Del Boca, F.K., & Darkes, J. (2003). The validity of self-reports of alcohol consumption: State of the science
and challenges for research. Addiction, 98, 1-12.
• Hoffmann, N. G. & Ninonuevo, F. G. (1994). Concurrent validation of substance abusers self-reports against
collateral information: Percent agreement vs. Kappa vs. Yule's Y. Alcoholism: Clinical and Experimental
Research, 18, 231-237.
• Midanik, L.T. (1988). Validity of self-reported alcohol use: A literature review and assessment. British Journal
of Addictions, 83,1019-1030.
• Woody, G.E., Poole, S.A., Subramaniam, G., Dugosh, K., Bogenschutz, M., Abbott, P., Patkar, A., Publicker,
M.,McCain, K., Potter, J.S., Forman, R., Vetter, V., McNicholas, L., Blaine, J., Lynch, K.G., Fudala, P., 2008.
Extended vs short-term buprenorphine-naloxone for treatment of opioid-addicted youth: a randomized trial.
JAMA 300, 2003-2011.
ACKNOWLEDGEMENTS
This research was supported by NIDA’s Clinical Trials Network