Transcript Related Journal Club Presentation

Journal Club
Alcohol, Other Drugs, and Health: Current Evidence
July–August 2010
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Featured Article
A Single-Question Screening Test
for Drug Use in Primary Care
Smith PC, et al. Arch Intern Med. 2010;170(13):1155–1160.
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Study Objective
• To validate a single-question screening test for
drug use and drug use disorders a in primarycare setting.
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Study Design
• Adult patients were recruited from a primary-care
clinic waiting room in a large US urban medical
center.
• To minimize bias, potential subjects were
approached using a predetermined pattern based
on waiting-room seating.
• Exclusion criteria were as follows:
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–
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Age <18 years
Very limited English language skills
Cognitive impairment
Acute illness
People accompanying patients but not patients themselves
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Study Design (cont’d)
• Of the 394 eligible patients approached, 286 (73%)
completed the screening interview.
• Participants were asked the following question: “How many
times in the past year have you used an illegal drug or
used a prescription medication for nonmedical reasons?”
– A response of ≥1 time was considered positive for drug use.
• Participants then completed the 10-item Drug Abuse
Screening Test (DAST), the Short Inventory of Problems–
Drug Use (SIP-DU), and the Composite International
Diagnostic Interview—Substance Abuse Module (CIDISAM).
• Responses were compared with oral fluid testing for illegal
drugs.
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Assessing Validity of an
Article About Diagnostic Tests
• Are the results valid?
• What are the results?
• Will the results help me in caring for my
patients?
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Are the Results Valid?
• Was there an independent, blind comparison with a
reference standard?
• Did the patient sample include an appropriate
spectrum of patients to whom the diagnostic test will
be applied in clinical practice?
• Did the results of the test being evaluated influence
the decision to perform the reference standard?
• Were the methods for performing the test described
in sufficient detail to permit replication?
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Was there an independent, blind
comparison with a reference standard?
• The CIDI-SAM was used as the reference
standard, as were results of oral fluid testing in
the 240 patients (84%) who consented to it.
• Data were recorded anonymously,
unaccompanied by any unique identifiers.
• It is not clear whether the research staff who
conducted the interviews also analyzed the data.
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Did the patient sample include an appropriate
spectrum of patients to whom the diagnostic
test will be applied in clinical practice?
• Yes.
• The population included all comers to a primary care
clinic and the sample included the spectrum from no
drug use through dependence.
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Did the results of the test being
evaluated influence the decision to
perform the reference standard?
• No.
– Both the single-question screen and reference
standard (CIDI-SAM) were administered to all
subjects. Saliva testing was not related to the results
of the screening test, although not all subjects agreed
to testing.
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Were the methods for performing
the test described in sufficient
detail to permit replication?
• Yes.
– The verbatim screening question was provided
in the article.
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What Are the Results?
• Are the likelihood ratios for the test
results presented or data necessary for
their calculation included?
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Are the likelihood ratios for the test
results presented or data necessary for
their calculation included?
• Yes.
– The sensitivity, specificity, likelihood ratios, and area
under the receiver operating curve (AUC) of the singlequestion screen were calculated for detection of
• drug use
• drug use associated with problems, and
• presence of a current drug use disorder.
– For comparison, the same ratios for detection of the
same conditions were calculated for the DAST-10.
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Will the Results Help Me in
Caring for my Patients?
• Will the reproducibility of the test result and its
interpretation be satisfactory in my setting?
• Are the results applicable to my patients?
• Will the results change my management strategy?
• Will patients be better off as a result of the test?
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Will the reproducibility of the test
result and its interpretation be
satisfactory in my clinical setting?
• Administration of the test and its results might
differ if asked by clinical versus research
personnel.
• Similarly, since responses were recorded
anonymously in this study, the same level of
validity might not be expected in a clinical
setting if recorded in a medical record.
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Are the results applicable to the
patients in my practice?
• Results likely apply to, at least, urban primary
care settings. A high proportion of the sample
had substance use disorders, reflecting the high
substance-use prevalence in the studied practice.
• Non-English speakers were excluded.
• 54% of participants were women.
• The majority of patients identified themselves as
black (63%), 17% as white, and 16% as
Hispanic. Results differed little by sex or race/
ethnicity.
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Will the results change my
management strategy?
• In circumstances in which it would be useful
to screen for drug use and drug-use
disorders, the validity and brevity of the
screening question may make screening
easier.
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Will patients be better off as
a result of the test?
• Identification of drug use by screening might
avoid drug interactions and other diagnostic and
therapeutic errors, and paves the way for early
intervention.
• Whether patients are in fact better off will
depend on follow up of positive screens with
skillful assessment, intervention, and/or referral
to specialized treatment.
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Summary/Clinical Resolution
• The single screening question accurately
identified drug use in this sample, supporting its
usefulness in primary-care settings.
• Although it cannot detect drug-use severity,
positive single-question screens can serve as
indicators that further assessment is warranted.
• This study had the following limitations:
– The proportion of participants reporting substance use disorders
was high, limiting the generalizability of results.
– Participants were assured anonymity. This improves the accuracy
of the reference standard interview, but may serve to
overestimate the accuracy of the screening test itself.
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