1. Using a discrete choice experiment with duration to estimate values for health states on the QALY scale Nick Bansback Assistant Professor School of Population and Public Health, University of British Columbia CIHR New Investigator

2. The Problem (1) Generic preference based measures (e.g EQ- 5D, HUI, SF-6D) may sometimes not be sensitive enough to capture important changes in health Espallargues M et al. The impact of age-related macular degeneration on health status utility values. Invest Ophthalmol Vis Sci. 2005 Nov;46(11):4016-23 McTaggart-Cowan et al. The validity of generic and condition-specific preference-based instruments: the ability to discriminate asthma control status. Qual Life Res. 2008 Apr;17(3):453-62.

3. The Problem (1) Generic preference based measures (e.g EQ- 5D, HUI, SF-6D) may sometimes not be sensitive enough to capture important changes in health As a result, there has been a huge increase in conjoint/ Discrete Choice Experiment studies looking at the value of more specific aspects of health

4. The Problem (2) DCE/conjoint studies have not produced values on the QALY scale. Hence none of these studies are amenable to incorporating into economic evaluation/informing policy

5. The Problem (2) DCE/conjoint studies have not produced values on the QALY scale. Hence none of these studies are amenable to incorporating into economic evaluation/informing policy Conventional elicitation approaches (Time Trade Off/Standard Gamble) are difficult to understand, and so tend to need a face to face interview – expensive and timely.

6. New Method: A discrete choice experiment with a duration attribute (referred to as DCEtto) Health State AHealth State B Some problems in walking about No problems in walking about No problems with self-careSome problems with self-care Some problems with performing my usual activities Moderate pain or discomfortNo pain or discomfort Not anxious or depressedExtremely anxious or depressed Live for 10 yearsLive for 7 years Choose A or B Health State AHealth State B Some problems in walking about No problems in walking about No problems with self-care Some problems with performing my usual activities No problems with performing my usual activities Moderate pain or discomfortNo pain or discomfort Not anxious or depressed Live for 10 years Live for t years Vary t until indifferent between A and B DCE Requires if health state A is preferred to B and not the degree by which A is preferred to B TTODCEtto

7. Estimation Value for health state j in Time trade off: Estimate model on DCE data where x represents vector or coefficients for each attribute level and t is the duration Use estimated coefficients… To solve 

8. Advantages to the DCEtto Simpler (fewer drop-outs) Enables incorporation of all respondents, increasing power and representativeness Cognition Included with no change in task or arbitrary transformation States worse than dead DCEs rooted in economic theory (RUT) Theory Quick to complete Can be implemented on the web (cheaper) Practical Bansback, et al. "Using a discrete choice experiment to estimate health state utility values." Journal of health economics 31.1 (2012): 306-318. Bansback, et al. "Testing a discrete choice experiment including duration to value health states for large descriptive systems: Addressing design and sampling issues." Social Science & Medicine 114 (2014): 38-48.

9. Case study New treatments for rheumatoid arthritis: Offer more convenient modes of administration But have less established evidence on long-term safety vs

10. Example DCE choice set

11. CoefftWTP InfusionRef Injection0.44*10.392.11 Tablet1.16*25.665.57 Twice dailyRef Once weekly0.21*4.870.99 Every 8 weeks0.41*9.851.97 40 people out of 100 benefitRef 55 people out of 1000.48*12.472.31 70 people out of 1001.20*28.275.75 15 people out of 100 withdrawRef 10 people out of 100 withdraw0.22*5.491.05 5 people out of 100 withdraw0.27*6.681.30 30 people out of 100 side-effect Ref 18 people out of 100 side-effect 0.30*7.881.42 5 people out of 100 side-effect 0.62*14.842.95 Limited confidence Ref Moderate confidence 0.23*5.881.12 Strong confidence 0.58*14.372.76 Life years (linear) 0.21*9.11 Number of responses 14980 Number of respondents 749 p2 0.214 Results (n=749) Market research panel – inexpensive 3 weeks for data collection Only 5 people dropped out 80 people failed consistency check, but their inclusion/exclusion does not change results Harrison M, Marra C, Shojania K, Bansback N. Societal preferences for rheumatoid arthritis treatments. Evidence from a Discrete Choice Experiment. Rheumatology. In Press

12. Results (on QALY scale)

13. Limitations Larger variance around results requires more responses than TTO studies In other DCEtto studies, questions remain about large range of values Worst EQ-5D state ~-0.6 Questions on how to incorporate into economic evaluation Clearer for developing values for condition specific non preference based QoL instruments (such as AQLQ) Possible double counting when combining with existing generic instruments

14. Questions Is the DCEtto really easier than the TTO? Should we be using this approach to combine more specific aspects of treatments with generic derived QALYs? How can we validate the approach further?