Download PRECIS-2 - UW Department of Family Medicine

The PRECIS-2 tool: Matching
Intent with Methods
David Hahn, MD, MS, WREN Director
Department of Family Medicine & Community Health
University of Wisconsin School of Medicine & Public Health
[email protected]
www.wren.wisc.edu
Agenda
• Explanatory and pragmatic trial concepts
• Introduce the PRECIS-2 tool
• Present an example from my research
• You score, I score
• Audience participation using your research
• We all score
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Definitions
•
Explanatory (~efficacy)
•
Can this intervention work under ideal
conditions?
•
Pragmatic (~effectiveness)
•
Does this intervention work under usual
conditions?
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Why is it important
to distinguish?
• To ensure that the trial results can indeed
support end user decisions in the ways
intended by the trial design team.
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Common mismatch
• Results of explanatory (efficacy) studies are too
often used in guidelines for general patient
populations that were not studied.
• Poor external validity risks inefficiencies and/or
unintended adverse consequences (i.e., less
benefit, more harm).
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Example for today
• Asthma treatment guidelines are based mainly
on explanatory studies that collectively exclude
~95% of people with asthma (Herland et al.
Respir Med 2005; Travers et al., Thorax 2007)
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AZMATICS
AZMATICS
Randomized
75/304 (25%)
If PFTs not required
77/304 (25%)
Declined placebo
34/304 (11%)
Important note
• PRECIS-2 is focused exclusively on
APPLICABILITY (external validity)
• Not a tool to gauge internal validity
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The Pragmatic-Explanatory Continuum Indicator Summary 2 (PRECIS-2) wheel
Eligibility
• As the similarity between people in the trial and
those in usual care decreases, then so would
the PRECIS-2 score.
• AZMATICS: adult asthma Dx and RAO; 30%
actual enrollment, 50% potential enrollment.
• Guideline trials: average 5% enrollment.
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Recruitment
• Via usual appointments in multiple clinics
receives a high (very pragmatic) score; via
media with incentives receives a lower score.
• AZMATICS: via usual care in multi-state
practices; no financial incentives.
• Guideline trials: Often via media; large
incentives
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Setting
• Good match between setting of trial and setting
where the results will be applied receives a higher
score.
• AZMATICS: conducted in settings where results
are applied.
• Guideline trials: Often in academic research
units.
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Organisation
• The greater the ease of implementation in
usual care the higher the PRECIS-2 score
• AZMATICS: oral tablet with simple instructions.
• Guideline trials: oral, inhaled or injectable
medications.
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Flexibility: delivery
• The closer the resemblance between trial
intervention and actual use, the higher the
PRECIS-2 score.
• AZMATICS: flexible dosing and scheduling,
particularly in open label (OL) group.
• Guideline trials: flexibility varies.
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Flexibility: adherence
• Trials with no special measures to enforce
compliance will score near 5; protocols that
measure and monitor compliance will score at
or close to 1
• AZMATICS: weekly self-report.
• Guideline trials: daily diaries, pill counts, even
metered dose inhaler electronic monitoring.
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Follow-up
• Outcome data obtained from routine visits with
no study visits is the most pragmatic; the more
intense the study follow up, the more
explanatory.
• AZMATICS: no study visits; Internet self-report.
• Guideline trials: often intense/rigorous study
visits.
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Primary outcome
• The more patient-important, the more
pragmatic; the more disease-oriented the more
explanatory.
• AZMATICS: symptoms, quality of life.
• Guideline trials: in transition from diseaseoriented (PFTs, biomarkers) to patientoriented.
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Primary analysis
• “Intention-to-treat” is the most pragmatic
approach; “as treated analysis” is the most
explanatory.
• AZMATICS: intention to treat.
• Guideline trials: varies; both may be reported.
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Now it’s your turn
• Choose a completed trial or a new protocol.
• Discuss for each domain.
• Come to a consensus on PRECIS-2 scores for
each domain.
• Reconvene to discuss the process.
www.wren.wisc.edu
The Pragmatic-Explanatory Continuum Indicator Summary 2 (PRECIS-2) wheel