The Arabic Arthritis Self-Efficacy Scale-8 (ASES-8): a valid and reliable measure of evaluating self-efficacy in Palestinian patients with rheumatoid arthritis

Background: The Arthritis Self-Efficacy Scale-8 (ASES-8) is one of the most commonly used scales to measure patient-reported arthritis-specific self-efficacy. However, evidence about the validity and reliability of ASES-8 in an Arabic-speaking arthritis population is lacking. Objective: This study aimed to cross-culturally adapt and assess aspects of validity and reliability of the Arabic version of the ASES-8. Methods: The ASES-8 was translated into the Arabic language using the back-translation method, and administered to 67 patients with rheumatoid arthritis (RA). Construct validation methods used exploratory factor analysis and correlating the ASES-8 scores with disease-related variables expected to be related to the arthritis self-efficacy construct. An internal consistency test was conducted. Floor and ceiling effects were considered present if more than 15% of patients achieved high (=10) and low (=1) scores on the Arabic ASES-8 for both the scale and item scores. Results: Exploratory factor analysis demonstrated a one-factor solution (factor loadings: 0.54–0.81). ASES-8 scores were correlated with all measures assessed (r = −0.24 to −0.57 and r = 0.06–0.66), demonstrating construct validity. Internal consistency was acceptable for measures of Cronbach’s alpha (0.86–0.88). The scale did not exhibit ceiling or floor effects. Conclusions: The Arabic version of ASES-8 is valid and reliable for evaluating self-efficacy in patients with rheumatoid arthritis.