How Do Individuals Value Worse-Than-Dead EQ-5D-5L Health States in Composite Time Trade-Off Tasks? A Qualitative Study

Objectives Limited knowledge exists regarding individuals’ thought processes when valuing health states using composite time trade-off (cTTO) tasks, particularly for health states considered worse than dead (WTD). This study aimed to explore the reasons for WTD perception, the strategies respondents used to value WTD states, and the challenges they faced during cTTO tasks. Methods This qualitative investigation was embedded within a methodological EQ-5D-5L valuation study involving the general public in Singapore, where respondents completed 7 cTTO and 7 novel TTO tasks. Semistructured interviews were conducted with respondents who assigned WTD values to 1 or more health states in the cTTO tasks. Interviews were recorded, transcribed verbatim, and analyzed using framework analysis. Results Nineteen respondents were interviewed (age range: 21-71 years old). Respondents identified a range of interconnected factors leading to WTD valuation, including health state and its duration, personal beliefs and circumstances, and consequences of poor health. Although respondents usually considered these factors thoroughly and were capable of complex trading-off between life years and health, some respondents resorted to heuristic strategies to simplify the valuation process, including attribute nonattendance, affect heuristic, and elimination-by-aspects strategies. Respondents encountered various difficulties when they completed the cTTO tasks, including identifying the indifference point, transitioning from conventional TTO to lead-time TTO, and interpreting and imagining health states. Conclusions This study investigated how individuals value WTD health states in cTTO tasks. It suggested that cTTO needs improvement and provided insights into how to improve the design of valuation tasks for severe health states.