2022 Volume 71 Issue 3 Pages 264-275
The use of quality-adjusted life year (QALY) as a measure of benefit is recommended in economic evaluation, which aims to provide evidence for the appropriate allocation of health care resources. This allows for an easier comparison of interventions' effects in different fields. A QALY value is calculated by weighting the life years (LYs) by the quality of life (QOL) score, which is determined by preference-based measure (PBM) and converted from 0 to 1. The QOL score should be obtained through domestic surveys because it reflects the value in the country's general population. In Japan, the data of the QOL scores for adults have been accumulated in recent years. However, few studies for children have been conducted due to various issues in evaluating pediatric health-related QOL (HRQOL). The PBM process for obtaining the QOL score can be divided into “measurement” and “valuation” of the health state to be evaluated. This process is implemented at once in direct methods, whereas it is carried out separately in indirect methods. Direct methods include the rating scale, the time trade-off, and the standard gamble, but children's feasibility, reliability, and validity must be thoroughly investigated. In indirect methods, which is currently the mainstream in general, multi-attribute utility instruments (MAUIs) are used, consisting of a questionnaire to measure the health state and a value set to value the measured health state. However, most MAUIs are designed for adult use and are not suitable for pediatric use because the questions are inappropriate, and the value set is intended to value adult health. In recent years, some MAUIs for pediatric use have been developed. Nevertheless, due to translations and the value set, these are not available in all countries. Additionally, there are no existing MAUIs available for children aged 3 years. Furthermore, issues concerning “measurement,” such as which domains should be assessed and how, and by whom, and issues concerning “valuation,” such as whose preferences should be reflected in developing the value set, and which perspectives should be used, remain. There have been no MAUIs for pediatric use in Japan, but the Japanese version of the EuroQol 5-dimension Youth version (EQ-5D-Y) and its value set have recently been published. It is necessary to fully understand the challenges and limitations in measuring and interpreting the QOL score in children.
