Adaptation and measurement invariance of the 13-item version of Patient Activation Measure across Japanese young adult cancer survivors during and after treatment: A cross-sectional observational study

Abstract

The 13-item version of the Patient Activation Measure (PAM-13) is a frequently used measure that gauges the level of self-management in an individual. However, its applicability across Japanese young adult (YA) cancer survivors during and after their treatment remains unclear. This study confirmed the psychometric properties and measurement invariance of the Japanese version of PAM-13 across them during and after treatment. We used cross-sectional observational data collected through an online survey from 500 survivors in January 2022. We determined feasibility, internal consistency, concurrent validity against physical fatigue and depression, and known-groups validity regarding educational level. Structural validity was also found using Rasch analysis for survivors both during and after treatment. Furthermore, measurement invariance of the PAM-13 was examined using multiple-group structural equation modeling. Rasch fit statistics were acceptable for the unidimensional structure of PAM-13. It was found to be internally consistent for survivors during (McDonald's omega: 0.88, item-total correlations: 0.48-0.62) and after treatment (McDonald's omega: 0.90, item-total correlations: 0.32-0.72). The PAM-13 was concurrently valid with physical fatigue (Pearson's product-moment correlation coefficients: -0.25 and -0.18 for survivors during and after treatment, respectively) and depression (Pearson's product-moment correlation coefficients: -0.20 and -0.19 for survivors during and after treatment, respectively). Known-groups validity showed that survivors after treatment with a higher educational level reported a higher patient activation score than those with a lower educational level (p = 0.001); however, there was no difference due to the education level between survivors during treatment. The configural and metric invariance of the PAM-13 were confirmed, but scalar invariance was rejected. It was found that the PAM-13 is applicable for Japanese YA cancer survivors during and after treatment. However, given the lack of scalar invariance in the PAM-13, the scores of particular items between YA cancer survivors during and after treatment should be interpreted with caution.