Cross Cultural Validation of Work Productivity and Activity Impairment Questionnaire in Lupus Patients From Latin America

Abstract

Objective: The objective of this study is to perform a cross-cultural validation of the Work Productivity and Activity Impairment (WPAI-Lupus v2.0) questionnaire in Latin American individuals with systemic lupus erythematosus (SLE), using data from the GLADEL cohort.

Methods: GLADEL 2.0 is an observational cohort of SLE patients ≥ 18 years old. Clinical data, disease activity (SLEDAI-2 K), damage index (SDI), physician's global assessment (PGA) and patient-reported outcomes (WPAI-Lupus v2.0, LupusQoL), were assessed at baseline and during follow-up. Construct validity was evaluated through Spearman correlations with SLEDAI-2 K, SDI and LupusQoL. Internal consistency was assessed using Cronbach's alpha and responsiveness over 12 months was analyzed using the Wilcoxon signed-rank test. Appropriate statistical tests (p < 0.05) were performed using R software, version 4.4.0.

Results: Among 1083 patients, 684 were evaluated at baseline and at 12 months. Cronbach's alpha values were: absenteeism 0.54; presenteeism 0.64; overall work impairment 0.62; activity impairment 0.62. WPAI-Lupus v2.0 scores correlated with SLEDAI-2 K (p < 0.001) and negatively with LupusQoL domains. Moderate correlations were observed between activity impairment and physical health, pain and planning (r ≈ -0.52 to -0.58). Presenteeism and overall work impairment also showed moderate correlations with physical health and pain domains (r ≈ -0.49 to -0.53). WPAI-Lupus v2.0 was sensitive to change over 12 months (p = 0.001) for all domains except intimate relationship.

Conclusions: WPAI-Lupus v2.0 demonstrated good validity, internal consistency, and responsiveness. It correlated with disease activity and quality of life, supporting the WPAI-Lupus v2.0 as a valid tool to assess work and activity impairment in Latin American patients with SLE.