Decision Analysis: Aspects of Medical Decision Making

1. Decision Analysis: Aspects of Medical Decision Making Gordon Hazen Northwestern University

2. Contributions • Decision analysis has contributed to decision-making in business, medicine, engineering, and law medicine, Stanford University October 2011

3. My Input to Today’s Discussion • The field of medical decision making • Relationships between medical decision analysis and the broader DA field • A nonscientific report based on my impressions only … Stanford University October 2011

4. The Field of Medical Decision Making • Modeling to aid diagnostic and therapeutic choice by physicians and treatment choice by patients • Cost-effectiveness modeling to inform public policy • Decision psychology: Understanding/ predicting patient and physician choices Stanford University October 2011

5. Relationships Statistics Health Economics Cost -Effectiveness Analysis Medical Decision Analysis Decision Analysis Decision Psychology Stanford University October 2011

6. Is methodological preparation enough? • No: Medical DA researchers are almost always attached to institutions serving real-world stakeholders • Bloomberg School of Public Health • Center for Disease Control and Prevention • Centre for Evaluation of Medicines (CEM), • Cleveland Clinic • Dept. of Social Medicine • Erasmus University Medical School • Center for Health Policy, Palo Alto, CA • Institute for Health, Health Care Policy and Aging Research • Mayo Clinic • MD Anderson Cancer Center • Merck • Minneapolis VA Ctr • Portland VA Medical Ctr • VA San Diego Healthcare System Stanford University October 2011

7. Journals • Publication of clinical decision analyses in medical journals is widespread • Frequently involve decision trees dovetailing into Markov models • PubMed search for 2010 with abstracts containing “Markov”: 1426 papers! • PubMed search for 2010 with abstracts containing “Markov” and titles containing “Effectiveness”: 200 papers. Stanford University October 2011

8. Journals • Journals with methodological focus • Medical Decision Making • Value in Health • International J. of Technology Assessment in Health Care • Health Economics • J. of Health Economics • Medical Care Stanford University October 2011

9. Examples of research (last three issues of Medical Decision Making) • Decision Psychology • Dynamics of Trust in Medical Decision Making: An Experimental Investigation into Underlying Processes • The 1-in-X Effect on the Subjective Assessment of Medical Probabilities • The Decision Making Control Instrument to Assess Voluntary Consent • The Influence of Narrative v. Statistical Information on Perceiving Vaccination Risks • Information for Decision Making by Patients With Early-Stage Prostate Cancer: A Comparison Across 9 Countries • Impact on Decisions to Start or Continue Medicines of Providing Information to Patients about Possible Benefits and/or Harms: A Systematic Review and Meta-Analysis • Preferences and Utilities • Estimation of a Preference-Based Carer Experience Scale • Eliciting Benefit–Risk Preferences and Probability-Weighted Utility Using Choice-Format Conjoint Analysis • Predicting EQ-5D Utility Scores from the Seattle Angina Questionnaire in Coronary Artery Disease: A Mapping Algorithm Using a Bayesian Framework Stanford University October 2011

10. Examples of research (last three issues of Medical Decision Making) • Provider Decision Making • How Long and How Well: Oncologists’ Attitudes Toward the Relative Value of Life-Prolonging v. Quality of Life-Enhancing Treatments • Deceiving Numbers: Survival Rates and Their Impact on Doctors’ Risk Communication • Electronic Notifications about Drug Substitutes Can Change Physician Prescription Habits: A Cross-Sectional Observational Study • Overestimation Error and Unnecessary Antibiotic Prescriptions for Acute Cystitis in Adult Women • Shared Decision Making • Longitudinal Changes in Patient Distress following Interactive Decision Aid Use among BRCA1/2 Carriers: A Randomized Trial • Are There Racial Differences in Patients’ Shared Decision-Making Preferences and Behaviors among Patients with Diabetes? • Risk Communication • Informing Patients: The Influence of Numeracy, Framing, and Format of Side Effect Information on Risk Perceptions • Influence of Graphic Format on Comprehension of Risk Information among American Indians • Graph Literacy: A Cross-Cultural Comparison Stanford University October 2011

11. Examples of research (last three issues of Medical Decision Making) • Exploring model structure • A Systematic Comparison of Microsimulation Models of Colorectal Cancer: The Role of Assumptions about Adenoma Progression • Clarifying Differences in Natural History between Models of Screening: The Case of Colorectal Cancer • How Does Early Detection by Screening Affect Disease Progression?: Modeling Estimated Benefits in Prostate Cancer Screening • Simulation of Quality-Adjusted Survival in Chronic Diseases: An Application in Type 2 Diabetes • Bayesian Inference for Comorbid Disease Risks Using Marginal Disease Risks and Correlation Information From a Separate Source • Can Life Expectancy and QALYs Be Improved by a Framework for Deciding Whether to Apply Clinical Guidelines to Patients With Severe Comorbid Disease? • Integrating Health Economics Into the Product Development Cycle: A Case Study of Absorbable Pins for Treating Hallux Valgus Stanford University October 2011

12. Examples of research (last three issues of Medical Decision Making) • Calibrating models • Estimating the Unknown Parameters of the Natural History of Metachronous Colorectal Cancer Using Discrete-Event Simulation • Bayesian Calibration of a Natural History Model with Application to a Population Model for Colorectal Cancer • Representing Uncertainty in Models • A Concise Equation That Captures the Essential Elements of One-Way Sensitivity Analyses in Health Economic Models • The Combined Analysis of Uncertainty and Patient Heterogeneity in Medical Decision Models • A Framework for Addressing Structural Uncertainty in Decision Models • Accounting for Methodological, Structural, and Parameter Uncertainty in Decision-Analytic Models: A Practical Guide Stanford University October 2011

13. Activity: SMDM versus INFORMS DA Cluster • SMDM 2006 • 314 Abstracts • 67 DA or C/E applications • 13 DA or C/E methodology • 127 utility/ preference/ dec’n psychology • INFORMS DA cluster 2006 • 93 Abstracts • 26 DA applications • 72 DA methodology • 8 utility/ preference/ dec’n psychology SMDM = Society for Medical Decision Making C/E = Cost-effectiveness Stanford University October 2011

14. Activity (Based on SMDM 2006 participation) • UK/Europe • University of Birmingham • University of York • University of Sheffield • University Medical Centre Utrecht • US • Harvard School of Public Health • Stanford University • Tufts-New England Medical Center • Boston University • Centers for Disease Control and Prevention • Case Western Reserve University School of Medicine • University of Pittsburgh • University of Chicago • Dartmouth Medical School • Duke University • Canada • University of Toronto • McMaster University • University of British Columbia • Univ of Western Ontario • University of Ottawa • Dalhousie University Stanford University October 2011

15. Academic PreparationSMDM Associate Editors: PhD areas • Psychology (4) • Epi-Biostat (2) • Economics (6) • Health Policy (2) • Health Econ (2) • Health Technology Assessment (2) • MD (4) Stanford University October 2011

16. Academic Preparation: What do these areas have in common? Decision Psychology Applied Math/Stat/OR Values and decisions under uncertainty Economics Health Stanford University October 2011

17. Impacts of the DA field on medical decision making • Decision psychology/ judgment and decision making • Thriving. Active research contributions. • Prescriptive decision analysis • Basics understood and accepted • Nuances not broadly understood • Sophisticated tools not used in practice Stanford University October 2011

18. Impacts of prescriptive DA on the medical field • Basics understood, accepted and used • Probability, utility • Decision trees • TreeAge software quite popular • Markov chains • Sensitivity analysis • Information value • Probabilistic sensitivity analysis • Bayesian probability and statistics Stanford University October 2011

19. Impacts of prescriptive DA on the medical field • Nuances are not broadly appreciated • The distinction between a utility function and a value function • Tacit belief that utility applies only to health states as opposed to any outcome of interest • QALYs = • “Cost-utility analysis” • Models of joint health and consumption not used • Howard 1984 • Smith & Keeney 2005 • Lichtendahl & Bodily 2009 Stanford University October 2011

20. Impacts of prescriptive DA on the medical field • Nuances are not broadly appreciated • The connection between preference assumptions on the one hand, and expected utility/ expected utility decomposition on the other. • Substitution/Independence (von Neuman & Morganstern) • Utility independence • The “preference assumptions  utility decomposition” game is not understood or played. Exceptions: • Pliskin, Shepard, Weinstein • Wakker • Miyamoto Stanford University October 2011

21. Impacts of prescriptive DA on the medical field • Sophisticated tools not employed • Influence diagrams • Utility decompositions beyond additive • One key exception: HUI (Feeney, Torrence, Furlong) • Copulas for constructing joint probability distributions • Scoring rules • Risk tolerance • Stochastic dominance • Combining expert judgments Stanford University October 2011

22. Impacts of prescriptive DA: Current research on QALYs • QALYs are the “utility function” for medical decision analyses • Foundations in preference theory • Pliskin, Shepard, Weinstein 1980 • Miyamoto, Wakker, Bleichrodt, Peters 1998 • Miyamoto 1999 • More for the prescriptive DA field to do? • Equity/distributive issues (Lipscomb 2009, Drummond 2009) • How to aggregate health impacts over time? Is QALY = too simplistic? (Lipscomb 2009) Stanford University October 2011

23. QALYs: More for the prescriptive DA field to do? • McHorney 2004 • Close to two dozen generic QOL instruments • Hundreds of disease-specific instruments • In cancer, over 75 different QOL measures exist • Fryback 2004 •  83 instruments for “General status and quality of life” • 6 generic instruments widely adopted • 36-Item Short Form Health Survey (SF-36) • WHOQOL-BREF Quality of Life Assessment • Quality of Well-Being scale (QWB-SA) • EuroQol EQ-5D • Health Utilities Index Mark 2 and Mark 3 • SF-6D, a preference-based measure derived from the SF-36 Stanford University October 2011

24. QALYs: More for the prescriptive DA field to do? • Instrument developers use psychometric techniques • classical test theory (CTT) • item response theory (IRT) • … to assess reliability, validity, difficulty, stability • These are not tasks for prescriptive DA. Stanford University October 2011

25. QALYs: More for the prescriptive DA field to do? Important issues: • Community preferences vs. preferences of those who have experienced a health state? (see Drummond 2009 ) • Different methods for valuing health yield different results • Standard gamble • Time tradeoff • Rating scale • Person tradeoff • Consensus that a standardized “reference method” is required for assessing QALYs • Reluctance to endorse “yet another summary measure” (Fryback 2004) • loss in ability to compare to previous research findings • Measure would not be universally adopted • These are not prescriptive DA issues … Stanford University October 2011

26. Health as a multiattribute concept • This is universally agreed to be the case. • Existing instruments all have multiple dimensions/attributes • but not the same ones … • HUI 2/3 both already based on multiattribute utility theory • More for prescriptive DA to do? Maybe not? • Reluctance to endorse “yet another summary measure” • Anything more complicated than additive or multiplicative might be too much of a “black box” to be accepted by practitioners Stanford University October 2011

27. ISPOR Development Workshop 2007 on “Moving the QALY Forward: Building a Pragmatic Road” • Eight-Item Consensus statement • QALYs are a health-based input, but there are other inputs to health decisions. • QALYs can be used for population-wide and individual health decisions • Little is known about the relationship between health and general well-being • Who should provide health value inputs? • Those who have experienced the health state? • Representative sample of community members? • Distributive/ equity issues need to be addressed. Stanford University October 2011

28. ISPOR Development Workshop 2007 on “Moving the QALY Forward: Building a Pragmatic Road” • Eight-Item Consensus statement • A need to better understand why different methods of QALY assessment give different answers • Need for better ways to aggregate health impacts over time HYEs theoretically superior but practically infeasible • A “Reference Method” is needed for QALYs • Which of these issues can be addressed by prescriptive DA? • Distributive/equity issues? • Health impacts over time? Stanford University October 2011

29. Summary • Decision psychology continues to make contributions to medical decision analysis • Decision psychology • Preference/ utility • Shared decision making • Risk communication • Prescriptive DA forms the basis for medical DA • Basic concepts and tools widely used • More sophisticated methods not understood and not applied • Health quality (QALYs) • Some opportunities for prescriptive DA contributions • The biggest stumbling blocks to progress do not appear solvable by prescriptive DA Stanford University October 2011

30. Questions/ comments to follow … Stanford University October 2011