PurposeThe purpose of this study was to measure the population norms for the Japanese versions of preference-based measures (EQ-5D-3L, EQ-5D-5L, and SF-6D). We also considered the relations between QOL score in the general population and socio-demographic factors. MethodsA total of 1143 adult respondents (aged ≥ 20 years) were randomly sampled from across Japan using data from the Basic Resident Register. The health status of each respondent was measured using the EQ-5D-3L, EQ-5D-5L, and SF-6D, and responses regarding socio-demographic data as well as subjective diseases and symptoms were obtained. The responses were converted to a QOL score using Japanese value sets. ResultsThe percentages of respondents with full health scores were 68 % (EQ-5D-3L), 55 % (EQ-5D-5L), and 4 % (SF-6D). The QOL score measured using the SF-6D was significantly lower than those measured using either EQ-5D score. The QOL score was significantly lower among respondents over the age of 60 years, those who had a lower income, and those who had a shorter period of education. Intraclass correlation coefficient showed a poor agreement between the EQ-5D and SF-6D scores. The differences in QOL scores between respondents with and those without any disease were 0.064 for the EQ-5D-3L, 0.061 for the EQ-5D-5L, and 0.073 for the SF-6D; these differences are regarded as between-group minimal important differences in the general population. ConclusionThe Japanese population norms of three preference-based QOL measures were examined for the first time. Such information is useful for economic evaluations and research examining QOL score.

The HLS-14 demonstrated adequate reliability and validity as a generic HL measure for Japanese adults. This scale can be utilized for measuring functional, communicative, and critical HL in the clinical and public health contexts.

Japanese value sets based on DCE were demonstrated. On comparing the observed cTTO scores, we found that the hybrid model was slightly superior to the simpler methods, including the TTO model.

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BackgroundIn economic evaluation, cost per quality-adjusted life year (QALY) is generally used as an indicator for cost-effectiveness. Although JPY 5 million to 6 million (USD 60, 000 to 75,000) per QALY is frequently referred to as a threshold in Japan, do all QALYs have the same monetary value?MethodsTo examine the relationship between severity of health status and monetary value of a QALY, we obtained willingness to pay (WTP) values for one additional QALY in eight patterns of health states. We randomly sampled approximately 2,400 respondents from an online panel. To avoid misunderstanding, we randomly allocated respondents to one of 16 questionnaires, with 250 responses expected for each pattern. After respondents were asked whether they wanted to purchase the treatment, double-bounded dichotomous choice method was used to obtain WTP values.ResultsThe results clearly show that the WTP per QALY is higher for worse health states than for better health states. The slope was about JPY −1 million per 0.1 utility score increase. The mean and median WTP values per QALY for 16 health states were JPY 5 million, consistent with our previous survey. For respondents who wanted to purchase the treatment, WTP values were significantly correlated with household income.ConclusionThis survey shows that QALY based on the EQ-5D does not necessarily have the same monetary value. The WTP per QALY should range from JPY 2 million (USD 20,000) to JPY 8 million (USD 80,000), corresponding to the severity of health states.