Psoriatic Arthritis Quality of Life questionnaire: Translation, cultural adaptation and validation into Arabic language.

Background: Psoriatic arthritis (PsA) is a multifaceted inflammatory disease that has a strong negative impact on the quality of life (QoL) of patients. The Psoriatic Arthritis Quality of Life (PsAQoL) questionnaire was the first disease-specific patient-derived instrument developed to measure the QoL in patients with PsA. Our objective was to translate the PsAQol into Arabic language and evaluate its reliability and validity in patients with PsA.

Methods: This was a cross-sectional study including patients with PsA. A clinical and biological assessment of the patients was performed at inclusion. The translation of the original PsAQoL into Arabic was performed by a professional bilingual and lay panel. Eight patients were interviewed to assess face and content validity. A separate sample of PsA patients (n = 30) were invited to participate in a test-retest postal study in order to investigate reproducibility and construct validity. One week separated the two administrations. The Arabic version of Health Assessment Questionnaire (HAQ) was used as a comparator instrument for convergent validity.

Results: Face and content validity were satisfactory. The Arabic version of the PsAQoL was found to be relevant, understandable and easy to complete in only a few minutes. One item was excluded (item 16). It had no correlation with either the other 19 items or the total score of PsAQol. The Arabic PsAQol had excellent internal consistency (Cronbach's a = 0.926), and test-retest reliability (r = 0.982). There was a positive correlation between the total score of the PsAQoL and the Arabic version of HAQ (Spearman's r = 0.838, p < 10^-3 ). Exploratory factor analysis had extracted two factors explaining 55% of the total variance.

Conclusion: Nineteen items were selected to compose the Arabic version of PsAQoL, which was found to be relevant and understandable and has excellent reliability and construct validity. The new measure will be a valuable new tool for use in routine care for patients' assessment.