The aim of this study was to investigate cross-cultural validity of the KDI among individuals with Katakori in Japan, Singapore, and the United States of America (USA).
Participants consisted of those aged 20–69 years with subjective Katakori. Data were collected by the survey companies through an anonymous online survey. The data of 100 Singaporeans, and 100 Americans, equally divided by age (20's, 30's, 40's, 50's, and 60's) and gender were collected. In addition to these data, the data of 515 Japanese divided almost equally by age group and gender as described above were analyzed. Multi-group confirmatory factor analysis (MGCFA) was conducted between the three nations, where missing values due to no such activities having taken place during the last week were inputted with score of 0 (i.e., no bothersomeness). In this study, cross-cultural validity was accepted if a partial metric invariance (i.e., a model with the constraint that the “factor loadings” of at least two of the constructs are equal across the three nations) was satisfied. Internal consistency of the KDI was assessed in each nation group. Mean KDI scores (0–14), with higher scores indicating greater disability, were compared among the three nations using one-way analysis of variance. Statical significance was set at 5%.
Missing values for each item ranged from 0% to 10% across all nation groups. The MDCFA demonstrated models that statistically satisfied the partial metric invariance criteria, indicating cross-cultural validity of the KDI. Cronbach’s alpha values were 0.91 for Japan, 0.94 for Singapore, and 0.92 for the USA, respectively. The mean (SD) of the average KDI scores were 5.0 (2.9) for Japan, 7.8 (3.2) for Singapore, 7.8 (3.3) for the USA, respectively, where statistically significantly greater disability (both p-values 0.001) was detected in the Singapore and USA groups than the Japanese group.
Cross-cultural validity of the KDI was detected among the populations of Japan, Singapore, and the USA.
The KDI has the potential to serve as a universal measure for Katakori-related disabilities. The KDI will be a foundation for future studies that aim to explore the effective management and prevention of Katakori.
patient-reported outcome measures
validity
