INTRODUCTION: Using various TTO methodologies. child health states (HS) typically result in higher utility values than adult HS. This effect may be attributed to the “immediate death” aspect of composite TTO (cTTO) valuations. AIM: To explore the effect of removing “immediate death” from cTTO valuation on youth HS valuation.

METHODS: Eighty responders (UK, Belgium, The Netherlands) participated in face-to-face interviews, and valued four HS (11221, 22222, 23332, 33333) from two perspectives (8-year-old child, 40-year-old adult). Two TTO methods were compared: composite TTO; and a modified version in which the person would not die after the 10-year period, but disappears instead. LYs could still be traded in the first 10-year period, after which the person would return to live a full life (=cTTO-FullLife). Thirty-two respondents also participated in a think-aloud interview during the valuation exercise.

RESULTS: The impact of perspective was an average increase in utilities for children versus adults, and this effect was growing with HS severity: +0.027, +0.114, +0.380, +0.298 for mild, moderate, severe and worst child HS (p<0.0001). The impact of the valuation method lead to a significant reduction in child utilities compared to adults, and this effect also increased with HS severity: -0.022, -0.036, -0.161, -0.146 for mild to worst HS (p=0.005). A generalized linear model showed that both perspective and valuation method were significant, independently of each other (both p<0.001). Qualitatively, these results were supported by statements on the increased likelihood of trading LY due to the person returning to live a full life, on the feasibility of this methodology, although questions were raised on the nature of the disappearance.

CONCLUSION: Removing “immediate death” from the cTTO valuation resulted in increased trading of LY across the whole range of HS severity. This effect could partly compensate the reduced trading effect typically found in youth cTTO-based valuation.