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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 [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 www.wren.wisc.edu Definitions • Explanatory (~efficacy) • Can this intervention work under ideal conditions? • Pragmatic (~effectiveness) • Does this intervention work under usual conditions? www.wren.wisc.edu 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. www.wren.wisc.edu 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). www.wren.wisc.edu 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) www.wren.wisc.edu 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 www.wren.wisc.edu 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. www.wren.wisc.edu 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 www.wren.wisc.edu 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. www.wren.wisc.edu 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. www.wren.wisc.edu 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. www.wren.wisc.edu 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. www.wren.wisc.edu 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. www.wren.wisc.edu 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. www.wren.wisc.edu 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. www.wren.wisc.edu 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