The EQ-5D is a generic, multidimensional, health-related, quality-of-life instrument. The profile allows participants to rate their health state in 5 health domains: mobility, self-care, usual activities, pain/discomfort, and mood using a three level scale (no problem, some problems, and major problems). These combinations of attributes were converted into a weighted health-state Index Score according to the Japan population-based algorithm ranging from -0.111 to 1.0, with higher scores indicating better quality of life.