LIHS Mini Master Class

Transcription

1 Alexandru Nicusor Matei 2013 CC BY-NC-ND 2.0 Value of Information Analysis Alison F. Smith Academic Unit of Health Economics (AUHE) A.f.c.smith University of Leeds This work is made available for reuse under the terms of the Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International Licence.

2 Outline Background Primer: Probabilistic Sensitivity Analysis (PSA) Expected Value of Perfect Information (EVPI) Expected Value of Perfect Parameter Information (EVPPI)

3 Why VOI? Decisions in the face of uncertainty are associated with a risk of making an incorrect decision Consequence of incorrect decision = Reduced health or increased cost Additional research has value in virtue of reducing the risk of making the wrong decision VOI Probability of incorrect decision = x Consequences of incorrect decision

4 Probabilistic Decision Modelling Efficacy Characteristics Adverse events Hospitalisation Decision Model Costs Effects Costs QoL

5 Monte-Carlo Simulation Efficacy Characteristics Costs Adverse events Hospitalisation Decision Model Effects Costs QoL

6 Monte Carlo Simulation Efficacy Characteristics Adverse events Hospitalisation Decision Model Cost Costs Effects QoL

7 Cost-effectiveness Plane

8 Expected Value of Perfect Information (EVPI) Cost-effectiveness expressed in terms of Net Health Benefit (NB): NB = E C/threshold Where E=expected effect, C=expected cost, threshold (willingness to pay per unit of effect)= 20,000 per QALY NB Treatment A NB Treatment B Optimal Choice Maximum net benefit Simulation B 12 0 Simulation A 12 2 Simulation B 20 0 Simulation A 11 1 Simulation A 14 1 Opportunity loss Expectation = EVPI EVPI = Expected NB with perfect information Expected NB with current information

9 EVPI Per person: Where j = treatment comparators, theta = uncertain parameters Population: Where t = effective lifetime of technology, I = annual incidence, and r = discount rate

10 EVPI Interpretation The EVPI provides information on the need for further research: The EVPI places an upper bound on the value of conducting further research A positive EVPI is a necessary condition for further research A positive EVPI is not a sufficient condition for further research

11 Must also consider: Does research reduce uncertainty Cost of research Duration of research Implications for patients subjected to experimentation Expected value of perfect parameter information (EVPPI) / Expected value of sample information (EVSI)

12 Expected Value of Perfect Parameter Information (EVPPI) Efficacy Characteristics Adverse events Hospitalisation Decision Model Cost Costs Effects QoL

13 population EVPI EVPPI 60m 50m 40m 30m 20m 10m Expected value of perfect parameter information for the treatment population m hazard ratio for DFS duration ofrecurrence benefit rate/type survival after relapse costs utilities QoL Parameter group

14 EVPPI Interpretation The EVPPI places an upper bound on the value of conducting further research on a particular parameter. As for EVPI a positive EVPPI is a necessary but not sufficient condition for conducting further research. It provides an indication of where future research should be focused.

15 Summary Should we do more research into an intervention? EVPI What sort of research? EVPPI (identify key parameters) EVSI (identify optimal research design)

16 Potential applications Recommendations for future research (late stage modelling) Efficient research possibilities: Research prioritisation (e.g. AKI Diagnostics) Grant applications for trials Adaptive trial designs (e.g. OPTIMA) Early stop/go decisions

17 Further Information Briggs A, Claxton K, Sculpher M. Decision Modelling for Health Economic Evaluation. Oxford Handbooks in Health Economic Evaluation. Oxford University Press. Oxford, UK [Ch 4&5 PSA; Ch 6&7 VOI] Claxton K.P. and Sculpher M.J. Using Value of Information Analysis to Prioritise Health Research: Some Lessons from Recent UK Experience. Pharmacoeconomics Briggs et al. Model Parameter Estimation and Uncertainty: A Report of the ISPOR_SMDM Modeling Good Research Practices Task Force-6. Value in Heath Hall PS, Edlin R, Karroubi S, Gregory W, McCabe C. Expected Net Present Value of Sample Information: from burden to investment. Medical Decision Making 32(3):E11-E21