Psychometric property of the Japanese version of self-efficacy for managing chronic disease scale in individuals with chronic diseases

Background: Although accurately assessing self-efficacy for self-management is crucial in chronic illness care, important, there is a scarcity of validated psychometric properties in Japan. This study aimed to validate a Japanese version of the Self-Efficacy for Managing Chronic Disease (SEMCD-J) scale. Methods: Individuals with self-reported chronic diseases, symptoms, or conditions for over one year were recruited online. The SEMCD-J was translated through translation, back translation, and cognitive interviews with 15 participants. Patient Health Questionnaire-9 (PHQ-9) and Center for Disease Control and Prevention Healthy Days Core Module-4 (CDC-HRQOL-4) were used to evaluate the scale's validity. Test-retest reliability was assessed two weeks after the initial measurement. Results: Of 500 participants, 494 were analyzed and 149 were analyzed for test-retest reliability. The mean item score was 5.54 ± 2.12. Confirmatory factor analysis (CFA) with a 1-factor model showed good fit (CFI = 0.94, TLI = 0.90, RMSEA = 0.23, SRMR = 0.04). CFA with a 2-factor model showed better fit (CFI = 0.99, TLI = 0.98, RMSEA = 0.11, SRMR = 0.01). Cronbach's α of the total, Factor 1, and Factor 2 were 0.97, 0.97, and 0.92. Their item-total correlations ranged from 0.88 to 0.95, 0.93 to 0.97, and 0.92 to 0.93, respectively. Their interclass correlation coefficients were 0.63, 0.58, and 0.66, respectively. The minimum detectable change was 3.56. Pearson's correlation analyses indicated that SEMCD-J was significantly associated with PHQ-9 (r = −0.57, p