OBJECTIVES

: In developed countries, progressive rapid aging is increasing the need for social care. Our research team has developed a Japanese version of the Adult Social Care Outcomes Toolkit (ASCOT) SCT4, which measures social care-related quality of life (ScRQOL) and uses for economic evaluation. This survey determined Japanese preference weights for the ASCOT SCT4.

METHODS

: We recruited 1050 Japanese respondents from 5 cities (Sapporo, Tokyo, Nagoya, Osaka, and Fukuoka) adjusted for age category and sex. In the best-worst scaling (BWS) phase, respondents were asked to rank various health states as “best”, “worst”, “second best” and “second worst”, as described by the ASCOT (repeating this process 8 times). After the BWS phase, they were asked to evaluate 8 different health states by composite time-trade off (cTTO). Four (BWS) and eight (TTO) blocks were randomly allocated to respondents. The nested logit model was used to analyze the BWS data, used by Netten et al. (2012). The association between scores as measured by cTTO and latent BWS scores was used to estimate a scoring formula that would convert BWS scores to utility scores.

RESULTS

: Japanese BWS weightings for ASCOT SCT4 were successfully estimated and found to be generally consistent with the UK preference weights. However, the coefficients "Control over daily life" and "Occupation" for level 3 differ markedly between the UK and Japan. The Japanese worst utility score was lower than UK because Japanese TTO results showed more negative valuations. In general, the Japanese preference score (for more than 90% of health states) was lower than that of the UK.

CONCLUSIONS

: We successfully obtained the Japanese preference weights for ASCOT. This is the first report to have developed Japanese SCRQoL preference weights using the ASCOT SCT4. Our study contributes to measurement and understanding of outcomes of social cares in Japan.