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Peruvian Valuation of the EQ-5D-5L: A Direct Comparison of cTTO and DCE

Background: Under the EuroQol Valuation Technology (EQVT) protocol, the composite time trade-off (cTTO) asks subjects to choose iteratively between health problems and reduced lifespan until indifferent, interpreted on a scale from 1 to - 1 QALY. In its discrete-choice experiment (DCE), subjects cho...

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Published in:The patient : patient-centered outcomes research 2020-02, Vol.13 (1), p.140-141
Main Authors: Augustovski, Federico, Belizan, Maria, Gibbons, Luz, Reyes, Nora, Stolk, Elly, Craig, Benjamin M, Tejada, Romina A
Format: Article
Language:English
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Summary:Background: Under the EuroQol Valuation Technology (EQVT) protocol, the composite time trade-off (cTTO) asks subjects to choose iteratively between health problems and reduced lifespan until indifferent, interpreted on a scale from 1 to - 1 QALY. In its discrete-choice experiment (DCE), subjects choose simply between two outcomes (paired comparison). Objectives: Our aims were to (1) produce EQ-5D-5L values from the perspective of Peruvian general population; (2) demonstrate the feasibility of a "Lite" protocol that relies on fewer subjects, and (2) directly compare cTTO and DCE value sets. Methods: A random sample of adults (N = 1000) was recruited in Lima, Arequipa and Iquitos for an interview survey. Some subjects (300) were randomly selected to first complete 11 cTTOs. All respondents were asked to complete 10 pairs with five EQ-5D-5L attributes and 12 matched pairs (A vs. B and B vs. C) with EQ-5D-5L and lifespan attributes. We estimated a cTTO heteroskedastic tobit (N = 300) model [1] and three DCE Zermelo-Bradley-Terry (ZBT) models (300, 700, and 1000) [2], each with the same 20 incremental parameters. Results: Each model produced a suitable value set (i.e., 20 positive parameters); however, their lowest values differed greatly (cTTO: - 1.076 [N = 300]; DCE: - 0.984 [300]; 0.048 [700], - 0.213 [1000]). Compared to the cTTO, the DCE (N = 300) produced different parameters (Pearson's correlation = 0.541), fewer insignificant parameters (0 vs 8) and fewer QALY values less than zero (26% vs 44%). The DCE values (n = 700) were higher, but similar (Pearson's correlation = 0.800). Conclusions: Apart from an EQ-5D-5L value set for Peru, the results demonstrate that the "Lite" protocol was feasible and illustrate fundamental differences between cTTO and DCE values. Because the values disagree, both methods may not be valid. Do Peruvian adults prefer "immediate death" (DCE) over almost half of the EQ-5D-5L outcomes (cTTO) or just a handful of extreme problems (DCE)?
ISSN:1178-1653
1178-1661