Evaluating the Validity and Reliability of Persian Version of Lupus Quality of Life (LupusQol) Questionnaire in Iranian Patients

Quality of life is of the most important outcomes measured in patients with systemic lupus erythematosus (SLE). The Lupus Quality of Life (LupusQoL) questionnaire is designed to specifically assess quality of life in these patients. This study aimed to evaluate validity and reliability of the Persian version of this questionnaire in Iranian patients.

LupusQol questionnaire was translated to Persian using the standard forward-backward translation method. Patients were asked to fill out the questionnaire. Cronbach`s alpha for the whole questionnaire and its 8 domains was measured. For construct validity, convergent validity and discriminant validity were evaluated. Also, known group validity was assessed by evaluating the correlation between quality of life and factors such as age, physical activity, concomitant diseases, disease activity and damage.

Seventy two patients with SLE with mean age of 36.7 ± 10.2 years were enrolled in this study. Cronbach`s alpha for the questionnaire was 0.94 and varied from 0.8 to 0.94 for the domains. The correlation coefficient of each item with its domain was more than 0.4 in all domains of LupusQol (convergent validity) and was more than the correlation of each item with other domains (discriminant validity). There was a significant correlation between age, physical activity, number of concomitant diseases and disease damage and most of the domains of the questionnaire (Correlation coefficient from 0.2 to 0.4).

The psychometric characteristics of the Persian version of LupusQol questionnaire are acceptable in Iranian population and this instrument can be used to evaluate quality of life in patients with SLE.