Background: Fabry disease is a rare X-linked lysosomal storage disorder. It is associated with physical distress and social challenges that may affect adults differently compared to pediatric patients. However, there is no disease-specific quality of life (QOL) scale that can provide a detailed assessment of QOL for adults with Fabry disease. Therefore, we aimed to determine the factor structure and assess the validity of a scale that was created to assess the QOL of adult patients with Fabry disease. This study was conducted in two phases. First, scale feasibility was confirmed through a questionnaire survey of nine patients. Second, a cross-sectional questionnaire survey of patients (aged ≥ 18 years) diagnosed with Fabry disease was conducted. Item development and refinement were conducted based on guidelines for scale development. Exploratory factor analysis was used to clarify the factor structure and confirm internal consistency. As a measure of QOL, construct validity was of the scale was verified based on its correlations with the Short Form-8 (SF-8) scale.
Results: The newly created Adult Fabry Disease QOL (AFQOL) scale comprises 39 items that cover five factors: "neuropathic pain and abdominal symptoms," "impact on work and school," "relationship challenges," "ophthalmologic and otolaryngologic symptoms," and "cardiovascular and renal symptoms." Cronbach's alpha coefficient for all factors was above 0.8, and the AFQOL total scores were significantly correlated with the physical and mental components of the SF-8 (rs = - 0.508 and - 0.400, respectively).
Conclusions: The AFQOL scale assesses physical symptoms and social difficulties experienced by adult patients with Fabry disease. A strength of the scale is its ability to assess the impact of work and relationships on patients. The scale can be useful in objectively assessing QOL for a group or for individual patients. Future research should explore further aspects of the scale's validity and reliability.
Keywords: Fabry disease; Patient-reported outcome measures; Quality of life; Scale development and validation; Surveys and questionnaires.
Adults with Fabry disease experience severe challenges, which adversely impact their quality of life (QOL). As it is a rare disease, non-patients lack awareness of the severity of its symptoms and the resultant social difficulties of the patients. Most instruments that measure QOL are not specific enough to address issues related to Fabry disease. Therefore, in this study, a measurement instrument known as the Adult Fabry QOL (AFQOL) scale was designed and validated. The 39-item scale covers five domains that are congruent with the symptoms of adult Fabry disease. It differs from other QOL scales as it also assesses the impact of work and personal relationships on patients’ QOL and symptoms that progress in adulthood. This study has important implications for healthcare providers who treat adult patients with Fabry disease, enabling them to have a fuller picture of the unique needs of this population.
© 2022. The Author(s).