David Hahn MD MS WREN Director Department of Family Medicine amp Community Health University of Wisconsin School of Medicine amp Public Health DLHahnwiscedu wwwwrenwiscedu Agenda Explanatory and pragmatic trial ID: 633476
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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
DLHahn@wisc.eduSlide2
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 scoreSlide3
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Definitions
Explanatory (~efficacy)
Can this intervention work under ideal conditions?
Pragmatic (~effectiveness)
Does this intervention work under usual conditions?Slide4
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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.Slide5
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Common mismatch
R
esults 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).Slide6
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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
)Slide7Slide8
AZMATICSSlide9
AZMATICS
Randomized
75/304 (25%)
If PFTs not required
77/304 (25%)
Declined placebo
34/304 (11%)Slide10
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Important note
PRECIS-2 is focused exclusively on APPLICABILITY (
external
validity)
Not a tool to gauge
internal
validitySlide11
The Pragmatic-Explanatory Continuum Indicator Summary 2 (PRECIS-2) wheelSlide12
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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.Slide13
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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 incentivesSlide14
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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.Slide15
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Organisation
The greater the e
ase
of implementation in usual
care the higher the PRECIS-2 score
AZMATICS: oral tablet with simple instructions.
Guideline trials: oral, inhaled or injectable medications.Slide16
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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.Slide17
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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.Slide18
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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.Slide19
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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 disease-oriented (PFTs, biomarkers) to patient-oriented.Slide20
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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.Slide21Slide22
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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.Slide23
The Pragmatic-Explanatory Continuum Indicator Summary 2 (PRECIS-2) wheel