Impact of Including Carer Information in Time Trade-Off Tasks: Results from a Pilot Study

Carer quality of life (QoL) can be included in economic evaluations and captured using EQ-5D. Traditional valuation tasks require participants to imagine living in a health state for a number of years, without being told what to consider. This pilot study sought to investigate whether participants implicitly consider the impact of the health state on others, and the extent to which this may impact health state valuations.

Composite time trade-off (TTO) interviews were conducted with a convenience sample. Each interview included a 'traditional' TTO exercise to value three health states, and a 'combined' TTO exercise, where participants valued the same health states again, having been informed that they would require a carer living in a particular health state. Qualitative feedback was collected after each exercise. Paired t-test comparisons of the utilities elicited in each exercise were made.

Thirty-three participants enrolled in the pilot. Mean differences between exercises were not statistically significant and differed in direction, although considerable heterogeneity was observed in individual response trajectories. Overall, 36% (n = 12) of participants expressed an unprompted concern about being a burden on others in the traditional exercise, and 67% (n = 22) of participants would have responded differently had the carer been in full health in the combined exercise.

Providing contextual information about carers may impact valuations. Further research is required to better understand the reasons behind the variation in individual response trajectories observed in this pilot study. The insights from this study may be useful for informing the design of related future studies.