An empirical study of two alternative comparators for use in time trade-off studies

Abstract

Studies to produce value sets for preference-based measures of health require definition of a full health upper anchor if the values are to be used to calculate quality-adjusted life years. Recent valuesetsderivedfortheEQ-5D-5Linstrumenthavedescribed the upper anchor as “full health,” whereas older valuation studies for the EQ-5Dused “best health state” in the descriptive system(11111). It is unclear whether this change could have led to differences in the values obtained. The objective of this study was to assess differences in time trade-off(TTO)valuations using two different comparators (full healthand11111). Methods: Preferences for EQ-5D 5Lhealth states were elicited from a broadly representative sample of the UK general public. TTO data were collected by using computer-assisted completed 10or11TTO valuations and a series of follow-up questions examining their interpretations of the term “full health.” Results: Interviews with 443 respondents were completed in 2014.The differences in mean values across arms are mostly small and non-significant. The two arms produced data of similar quality. There is evidence of interviewer effects .Health state 11111 was given a value of 1 by 98.2% of the respondents who valued it. Conclusions: EQ-5D-5L values elicited by using the composite TTO approach are not greatly affected by the use of full health or 111 11as the comparator health state. personal interviews. Respondents were randomly allocated to one of two arms, each using a different comparator health state.