Abstract
Self-efficacy is the belief that one can perform a specific behavior or task in the future, and it has been associated with physical and psychological aspects in people with chronic musculoskeletal disorders. The self-efficacy of individuals with arthritis can be assessed using the Arthritis Self-Efficacy Scale. The 8-item Short-Form ASES (ASES-8) has been employed in recent times. However, the reliability and validity of the Japanese ASES-8 (ASES-8J) have not been investigated. Therefore, this study aimed to investigate the reliability and validity of the ASES-8J. Overall, 179 Japanese participants with knee osteoarthritis (OA) were enrolled. Cronbach's alpha was calculated to confirm internal validity. Intraclass correlation coefficients (ICCs) were used to estimate test-retest reliability. Construct validity was analyzed using the Pain Self-Efficacy Questionnaire (PSEQ) and the problem-solving and positive thinking subscales of Brief Coping Orientation to Problems Experienced (Brief COPE). Discriminant validity was analyzed by comparing "worse" and "better" groups based on pain severity; short-form version of Depression, Anxiety, and Stress Scale-21 (DASS-21); Brief Fear of Movement Scale for Osteoarthritis (BFOMSO); Pain Catastrophizing Scale (PCS); and physical function subscale of Western Ontario and McMaster Arthritis Index. Cronbach's alpha and ICC were 0.94 and 0.81, respectively. Correlation coefficients among ASES-8J, PSEQ, and Brief COPE problem-solving and positive thinking subscales were 0.42, 0.43, and 0.32, respectively. Regarding the depression and stress subscales of DASS-21, BFOMSO, and PCS, the worse group showed significantly lower ASES-8J scores than the better group. Coefficients of correlation among ASES-8J, PSEQ, and the problem-solving and positive thinking subscales of Brief COPE were low to moderate. These findings suggest that the ASES-8J is a valid and reliable tool for assessing self-efficacy in Japanese patients with knee OA and can facilitate comparisons of arthritis self-efficacy between Japanese patients and non-Japanese patients.