Evaluation of the Measurement Properties of the German LupusPRO™ for Swiss-German SLE Patients
Author(s)
Chris Buckley, MSc1, Alessandra Girardi, PhD2.
1Associate, Clinical Outcomes Assessment, PAREXEL, Hayling Island, United Kingdom, 2Parexel, Milan, Italy.
1Associate, Clinical Outcomes Assessment, PAREXEL, Hayling Island, United Kingdom, 2Parexel, Milan, Italy.
OBJECTIVES: The LupusPRO™ is a valuable instrument in determining how Systemic Lupus Erythematosus (SLE), a multi-system autoimmune disease, impacts health-related quality of life (HRQoL). This study aimed to confirm the measurement properties of the German adaptation of the LupusPRO™ administered to Swiss, German-speaking SLE patients.
METHODS: Data collected from 108 German-speaking adults with SLE from Switzerland, were included in the study. The HRQoL section of the LupusPRO™ consists of 30 items rated on a 5-point Likert scale designed to evaluate eight domains: symptoms, cognition, medication, procreation, physical health, pain/fatigue, emotional health, and body image. Analyses included floor/ceiling domain score distribution, internal consistency reliability, convergent validity with the Systemic Lupus Activity Questionnaire (SLAQ), known group validity, and Confirmatory Factor Analysis (CFA).
RESULTS: Domain median scores ranged from 34.7 to 75.0. Floor and ceiling effects were observed in some domains. Internal consistency was generally acceptable, with Cronbach's α below the recommended threshold for symptoms, procreation, and medication domains. Convergent validity between LupusPRO™ and SLAQ was confirmed. Known group validity showed significant differences between patients with and without recent lupus flares for most domains. CFA supported the conceptual framework with acceptable model fit (CFI = 0.90, TLI = 0.88, RMSEA = 0.073, SRMR = 0.059) and satisfactory item-to-factor loadings.
CONCLUSIONS: The German adaptation of LupusPRO™ demonstrates robust measurement properties in Swiss SLE patients, aligning with previous cross-cultural validation studies. Most domains showed acceptable to excellent internal consistency, with some exceptions. Ceiling and floor effects were evident in medication, body image, and procreation, aligning with previous studies. Convergent, known-group and structural validity were confirmed, though the 'loss of hair' item may require reconsideration within the symptoms construct. Overall, this proves to be a valid and reliable tool offering clinicians and researchers a comprehensive, culturally appropriate measure to understand and address the complex needs of this patient population.
METHODS: Data collected from 108 German-speaking adults with SLE from Switzerland, were included in the study. The HRQoL section of the LupusPRO™ consists of 30 items rated on a 5-point Likert scale designed to evaluate eight domains: symptoms, cognition, medication, procreation, physical health, pain/fatigue, emotional health, and body image. Analyses included floor/ceiling domain score distribution, internal consistency reliability, convergent validity with the Systemic Lupus Activity Questionnaire (SLAQ), known group validity, and Confirmatory Factor Analysis (CFA).
RESULTS: Domain median scores ranged from 34.7 to 75.0. Floor and ceiling effects were observed in some domains. Internal consistency was generally acceptable, with Cronbach's α below the recommended threshold for symptoms, procreation, and medication domains. Convergent validity between LupusPRO™ and SLAQ was confirmed. Known group validity showed significant differences between patients with and without recent lupus flares for most domains. CFA supported the conceptual framework with acceptable model fit (CFI = 0.90, TLI = 0.88, RMSEA = 0.073, SRMR = 0.059) and satisfactory item-to-factor loadings.
CONCLUSIONS: The German adaptation of LupusPRO™ demonstrates robust measurement properties in Swiss SLE patients, aligning with previous cross-cultural validation studies. Most domains showed acceptable to excellent internal consistency, with some exceptions. Ceiling and floor effects were evident in medication, body image, and procreation, aligning with previous studies. Convergent, known-group and structural validity were confirmed, though the 'loss of hair' item may require reconsideration within the symptoms construct. Overall, this proves to be a valid and reliable tool offering clinicians and researchers a comprehensive, culturally appropriate measure to understand and address the complex needs of this patient population.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
MSR99
Topic
Methodological & Statistical Research
Topic Subcategory
PRO & Related Methods, Survey Methods
Disease
No Additional Disease & Conditions/Specialized Treatment Areas, Systemic Disorders/Conditions (Anesthesia, Auto-Immune Disorders (n.e.c.), Hematological Disorders (non-oncologic), Pain)