Transcript Related Journal Club Presentation

Journal Club
Alcohol and Health: Current Evidence
July–August 2005
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Featured Article
Screening for hazardous or harmful
drinking using one or two
quantity-frequency questions
Canagasaby A, Vinson DC. Alcohol Alcohol. 2005;40(3):208–213.
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Study Objective
To compare the performances of
brief screening tests to detect
unhealthy alcohol use
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Study Design
• Investigators screened…
– 1537 emergency department patients with an acute
injury,
– 1151 emergency patients with a medical illness
– 1112 randomly selected people contacted by telephone
• Researchers first asked each subject…
– a question about alcohol consumption in a day
(“When was the last time you had more than X drinks in
1 day?” with X being 5 for men and 4 for women)
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Study Design (cont.)
• They asked subjects who reported drinking >=6 drinks
in the past year 2 standard questions about quantity and
frequency of consumption:
– the average number of drinks per occasion
– the frequency of drinking (5-point ordinal scale from “less than
once a month” to “almost every day”)
• Diagnostic interviews (the Diagnostic Interview
Schedule) determined the presence of an alcohol use
disorder (based on the Diagnostic and Statistical Manual
of Mental Disorders, DSM IV).
• Validated calendar methods determined drinking
amounts.
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Assessing Validity of an
Article about Diagnostic Tests
• Are the results valid?
• What are the results?
• How can I apply the results to patient
care?
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Are the Results Valid?
• Did clinicians face diagnostic uncertainty?
• Was there a blind comparison with an
independent gold standard applied similarly
to the treatment group and the control
group?
• Did the results of the test being evaluated
influence the decision to perform the
reference standard?
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Did clinicians face diagnostic
uncertainty?
• Because of the nature of screening (testing
people regardless of symptoms of the target
disorder), there was inherent diagnostic
uncertainty.
– Diagnoses were not known prior to
testing.
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Was there a blind comparison with an
independent gold standard applied similarly to
the treatment group and the control group?
• There was a comparison with a “gold” (reference)
standard applied to all subjects.
– The reference standard was a structured
interview conducted by trained research staff.
• Staff was not blinded to the answers provided by
subjects.
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Did the results of the test being
evaluated influence the decision to
perform the reference standard?
• No:
– Everyone completed the reference standard.
– However, the diagnostic reference standard
(though well-accepted and extensively
validated) defines people who deny having
had >=6 drinks in the past year as having no
alcohol use diagnosis.
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What Are the Results?
• What likelihood ratios were associated
with the range of possible test results?
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What likelihood ratios were associated
with the range of possible test results?
• At a specificity of at least 70%, the single
question about alcohol consumption in a
day had the best sensitivity.
• A response of “in the last 3 months” was
associated with the following likelihood
ratios:
– For women: positive test 3.6; negative test 0.2
– For men: positive test 2.8; negative test 0.2
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How Can I Apply the Results to
Patient Care?
• Will the reproducibility of the test result and its
interpretation be satisfactory in my clinical setting?
• Are the results applicable to the patients in my
practice?
• 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?
• The interpretation is not difficult.
• Reproducibility is uncertain since the
screening questions were asked by trained
research staff.
• The question is not difficult to ask and
training is not required; however, patients
may be less forthcoming with their own
caregivers.
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Are the results applicable to the
patients in my practice?
• The results appear to have broad
applicability since screening occurred in
emergency and general population
samples.
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Will the results change my
management strategy?
• Results could change patient management.
– Like previous studies, this study found that
the single alcohol screening question has
excellent sensitivity and specificity.
– Current practice is to use questions that are
not validated, or more rarely, to use 4- or
10-item validated screening questionnaires.
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Will the results change my
management strategy? (cont.)
• Use of a single screening question appears
to be valid and much more likely to be
employed in busy clinical practice.
• In a new guide for clinicians, the National
Institute on Alcohol Abuse and Alcoholism
recommends a similar single question for
alcohol screening.
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Will patients be better off as
a result of the test?
• Yes; patients will benefit from this approach
to screening.
– Screening followed by brief intervention, when
indicated, in primary care settings has proven
efficacy for decreasing risky drinking in
nondependent drinkers.
– Patients identified by screening who have alcohol
dependence may also benefit from referral to
specialty treatment.
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Summary/Clinical Resolution
• A single question asking about the last time a
patient drank excessively can detect
unhealthy alcohol use including risky drinking
and alcohol use disorders.
• The only methodological caveat is that the
full diagnostic reference standard used in this
study was not completed in very light
drinkers.
– However, the caveat is a small one since it is unlikely that
many people who report drinking <6 drinks per year would
have unhealthy alcohol use.
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