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Journal Club
Alcohol, Other Drugs, and Health: Current Evidence
January–February 2015
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Featured Article
Association of opioid agonist therapy
with lower incidence of hepatitis C virus
infection in young adult injection drug
users
Tsui JI, et al. JAMA Intern Med. 2014;174:1974–1981.
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Study Objective
• To determine whether opioid agonist
therapy (OAT) was associated with a lower
incidence of hepatitis C virus (HCV)
infection among a population of young
people (<30 years) with injection drug use
(IDU).
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Study Design
• Observational cohort study of 552
young people with IDU and without
HCV infection at baseline, 2000-2013.
– Quarterly interviews and blood sampling.
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Assessing Validity of an
Article about Prognosis
• 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?
• Was the sample representative?
• Were the subjects sufficiently homogeneous with
respect to prognostic risk?
• Was follow-up sufficiently complete?
• Were objective and unbiased outcome criteria
used?
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Was the sample representative?
All subjects in this study were…
• under 30 years of age
• had IDU
• were negative for anti-HCV antibody and/or HCV RNA
at baseline
• Exposures: “Substance use treatment within the past 3
months, including non-opioid agonist forms of treatment, opioid
agonist (methadone hydrochloride or buprenorphine
hydrochloride) detoxification or maintenance therapy, or no
treatment.”
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Were the subjects sufficiently
homogeneous with respect to prognostic
risk?
• Yes.
– Participants were under 30 years of age and
had IDU in the past month
– 33% had daily IDU in the past month
– 4% had HIV at baseline
– 78% had used needle exchange in the past
month
– 82% had never had any kind of treatment for
drug use
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Was follow-up
sufficiently complete?
•
The study was conducted over 13 years for a
total of 690 person-years.
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Were objective and unbiased
outcome criteria used?
• Yes
– Primary outcome was incident HCV infection
– All subjects were tested quarterly
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What Are the Results?
• How likely are the outcomes over time?
• How precise are the estimates of
likelihood?
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How likely are the outcomes over time?
• Over the course of the study, 171 incident
cases of HCV infection occurred (incidence
rate, 25.1 [95% CI, 21.6-29.2] per 100
person-years).
• After adjustment, opioid agonist therapy was
associated with lower relative hazards for
acquiring HCV infection over time (adjusted
hazard ratio, 0.39 [95% CI, 0.18-0.87];
P = .02).
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How precise are the estimates
of likelihood?
• The confidence intervals were narrow.
– AHR for incident HCV infection among people who
had OAT: 0.39 (0.18-0.87, 95% CI), P = 0.02
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How Can I Apply the Results
to Patient Care?
• Were the study patients and their management
similar to those in my practice?
• Was follow-up sufficiently long?
• Can I use the results in the management of
patients in my practice?
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Were the study patients similar
to those in my practice?
• The inclusion criteria were broad, although
restricted to young individuals with injection
drug use.
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Was follow-up sufficiently long?
• Yes. The study period was 13 years.
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Can I use the results in the
management of patients in my practice?
• Yes. This study shows that HCV is still a
common hazard for people with IDU and
confirms prior observations that OAT reduces
the risk of acquiring this infection.
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