Validation and reliability of a disease-specific quality-of-life measure in patients with cutaneous lupus erythematosus.

Abstract

Cutaneous lupus erythematosus (CLE) is a potentially disfiguring, chronic autoimmune disease with variable skin manifestations, negatively affecting patients' quality of life (QoL). Patient-reported outcome (PRO) measures assessing QoL in patients with CLE have been generic or developed without input from patients. To demonstrate the reliability and validity of a disease-specific QoL measure for CLE - the cutaneous lupus erythematosus quality of life (CLEQoL). One hundred and one patients with CLE were recruited, and each patient was asked to complete the CLEQoL. Internal consistency was used as a measure of reliability. Validity was measured in two ways - structural validity via exploratory factor analysis and convergent validity via Spearman correlations between CLEQoL and the Short Form 36 (SF-36), visual analogue scales and clinical variables. Patient demographic and disease characteristics were collected. The mean ± SD age of patients with CLE was 48 ± 13 years, with discoid lupus (n = 72; 71.3%) being the most predominant CLE subtype. Patients were mostly female (n = 88; 87·1%) and African American/Black (n = 59; 58·4%). Internal consistency ranged from 0·67 to 0·97. Five domains (functioning, emotions, symptoms, body image/cosmetic effects and photosensitivity) were extracted with a total explained variance of 71·1%. CLEQoL-related domains correlated with SF-36 domains (r range -0·39 to -0·65). The CLEQoL was found to be a valid and reliable PRO measure for assessing QoL in patients with CLE. Demonstrating that the CLEQoL has strong psychometric properties is an important step towards the development of a disease-specific PRO measure that future clinical trials can use.