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Cost-Effectiveness Analysis and the Value of Research. David Meltzer MD, PhD The University of Chicago. Overview. Cost-effectiveness analysis has long been used to assess the value of medical treatments and the information that comes from diagnostic tests
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Cost-Effectiveness Analysis and the Value of Research David Meltzer MD, PhD The University of Chicago
Overview • Cost-effectiveness analysis has long been used to assess the value of medical treatments and the information that comes from diagnostic tests • Newer value of information techniques have extended these tools to assess the value of medical research • Understanding behaviors determining use of medical interventions in the context of heterogeneity is key to assessing their value and priorities for research • Research may be especially valuable when it can be used to individualize care
Value of Medical Treatments • Health effects • Length/quality of life: QALYs • Cost effects • Choose all interventions for which Dcost/DQALY < threshold • Often $50-100K/QALY • Widely accepted, >> 1000 applications
Value of Diagnostic Testing U(T|S) S Test pU(T|S)+(1-p)U(N|H) U(N|H) H S Max{pU(T|S)+(1-p)U(T|H), pU(N|S)+(1-p)U(N|H)} Don’t Test H
Testing as Value of Information U(T|S) S Test pU(T|S)+(1-p)U(N|H) U(N|H) H S Max{pU(T|S)+(1-p)U(T|H), pU(N|S)+(1-p)U(N|H)} Don’t Test H
Research as Value of Information U(T|S) S Test pU(T|S)+(1-p)U(N|H) U(N|H) H S Max{pU(T|S)+(1-p)U(T|H), pU(N|S)+(1-p)U(N|H)} Don’t Test H
Value of Information Approach to Value of Research • Without information • Make best compromise choice not knowing true state of the world (e.g. don’t know if intervention is good, bad) • With probability p: get V(Compromise|G) • With probability 1-p: get V(Compromise|B) • With information • Make best decision knowing true state • With probability p: get V(Best choice|G) • With probability 1-p: get V(Best choice|B) • Value of information = E(outcome) with information - E(outcome) w/o information = {p*V(Best choice|G) + (1-p)*V(Best choice|B)} - {p*V(Compromise|G) + (1-p)*V(Compromise|B)} = Value of Research
Practical Applications of Value of Information • Several full applications • UK (NICE): Alzheimer’s Disease Tx, wisdom teeth removal • US (AHRQ): Hospitalist research • But needed data can be hard to obtain • Bound with more limited data • Murphy/Topel: DLE 3mo/yr*$50K/LY = $10K/person/yr = $3 Trillion/yr • Real value of research may be far less than expected, e.g., for prostate cancer: • Maximal value of research = $ 5 Trillion • Expected value of perfect information = $21 Billion • Expected value of information = $ 1 Billion • Area of active investigation • Most promising clearly for applied research
“Bayesian Value of information analysis: An application to a policy model of Alzheimer's disease.”
Practical Applications of Value of Information • Several full applications • UK (NICE): Alzheimer’s Disease Tx, wisdom teeth removal • US (AHRQ): Hospitalist research • But needed data can be hard to obtain • Bound with more limited data • Murphy/Topel: DLE 3mo/yr*$50K/LY = $10K/person/yr = $3 Trillion/yr • Real value of research may be far less than expected, e.g., for prostate cancer: • Maximal value of research = $ 5 Trillion • Expected value of perfect information = $21 Billion • Expected value of information = $ 1 Billion • Area of active investigation • Most promising clearly for applied research • Increasing interest among pharma
Behavioral Cost-Effectiveness Analysis • Value of health interventions depend on how they are used • Especially in the presence of heterogeneity • True for treatments and for diagnostics • Understanding behaviors determining use of health interventions key to their evaluation • Optimizing behavior: self-selection/diagnostic testing • Non-optimal behavior: non-selective use
Standard CEA with Heterogeneous Individuals CE D costs m D effectiveness Blue Dots = Treated Patients
Optimal Selection with Heterogeneity: via Self-selection or Diagnostic Testing CE D costs m D effectiveness Blue Dots=Pts gain from Tx; Orange Dots=Pts lose from Tx
Effect of Perfect Selection on CEA CE D costs m m’ D effectiveness Blue Dots=Pts gain from Tx; Orange Dots=Pts lose from Tx (reject)
Empirical Selection CE D costs m D effectiveness Blue Dots=Pts choose Tx; Orange Dots=Pts reject Tx
Background: Diabetes in the Elderly • Diabetes care guidelines call for intensive lowering of glucose among younger patients • However, unclear if this should apply to older patients • Gains in life expectancy smaller • Side effects of treatment may dominate • CE models of intensive therapy in older patients: • Minimal or even negative effects on QALYs • Not cost-effective • Know many patients refuse intensive therapy • Suggests self-selection may have important effects on CEA in diabetes
Methods • Interviewed 500 older diabetes patients to obtain data on preferences • Conventional and intensive glucose lowering (using insulin or oral medications) • Blindness, end-stage renal disease, lower extremity amputation • Collected data on treatment choices and patient characteristics by medical records review • Used CDC simulation model of intensive therapy for type 2 diabetes and patient-specific demographic, health, and preference data to get person-specific estimates of lifetime costs and benefits • Analyses of cost-effectiveness of intensive vs. conventional therapy contrasting all patients vs. perfect self-selection vs. empirical self-selection
Perfect Self-Selection Effect for Intensive Therapy CE m m’ Blue dots--the cost-effectiveness values of individuals with an expected benefit from intensive therapy. Orange dots-- the cost-effectiveness values of individuals with a decrement in expected benefits with intensive therapy. M-- CE ratio for whole population. M’—CE ratio after self-selection.
Empirical Self-Selection Effect for Intensive Therapy Blue dots-- cost-effectiveness values for individuals who identify their care as intensive therapy. Orange dots-- cost-effectiveness values for all other individuals. M-- CE ratio for orange dot individuals. M’-- CE ratio for blue dot individuals.
Implications - I • Results of standard CEA may be misleading • In contrast to the suggestion of standard CEA, offering intensive glucose lowering to all older people likely cost-effective • CEAs should consider the importance of self-selection • Distinction between perfect and empirical self-selection is potentially important • Data on who will use a treatment if it is offered is important
Implications - II • A framework to account for heterogeneity in patient benefits is key to valuing diagnostic tests, guidelines, decision-aids, or improved patient-doctor communication that can make care more consistent with variation in patient benefits
Motivation for Diagnostic Test/Decision Aids CE D costs m D effectiveness Blue Dots=Pts choose Tx; Orange Dots=Pts reject Tx
Aim of Diagnostic Test/Decision Aids CE D costs m D effectiveness Blue Dots=Pts choose Tx; Orange Dots=Pts reject Tx
Value of Diagnostic Test/Decision Aids CE D costs m D effectiveness Dc De Blue Dots=Pts choose Tx; Orange Dots=Pts reject Tx
Value of Diagnostic Test/Decision Aid • Effectiveness = Pts D De • Costs = Pts D Dc • Total Benefit Cost-Benefit = (1/l) Pts D De + Pts D Dc Net Health Benefit = Pts D De + l Pts D Dc
Per Capita Value of Identifying Best Population-level and Individual-level Treatment in Prostate Cancer
Implications - III • Modeling heterogeneity and selection suggests a framework to design co-payment systems to enhance the cost-effectiveness of therapies
Motivation for Copayment (pc) CE pc D costs m D effectiveness Blue Dots=Pts choose Tx; Orange Dots=Pts reject Tx
Motivation for Copayment (pc) CE pc D costs m D effectiveness Blue Dots=Pts choose Tx; Orange Dots=Pts reject Tx
Per Capita Value of Identifying Best Population-level and Individual-level Care in Prostate Cancer with Full Insurance
Conclusions • Cost-effectiveness analysis can be used to value diagnostic testing and research on diagnostic testing • Approaches exist to bound calculations with limited data • Understanding behaviors determining use of medical interventions in the context of heterogeneity is key to assessing their value and priorities for research • Research may be especially valuable when it can be used to individualize care • Insurance and other determinants of use can significantly alter value of research
Implications of Empirical CEA • Need to consider how a treatment will be used in deciding if it will be welfare improving • Highlights importance of efforts to promote selective use of treatments • Biomarkers valuable if encourage selective use of treatments • Need to consider how a biomarker will be used in deciding if it will be welfare improving • Highlights importance of efforts to promote selective use of biomarkers • Biomarkers valuable if encourage selective use of treatments
Non-selective Use and Empirical Cost-effectiveness • Cost-effectiveness analyses of interventions often stratify cost-effectiveness by indication • Yet technologies are often used non-selectively • The actual (empirical) costs and effectiveness of an intervention may be strongly influenced by patterns of use