Abstract
IntroductionCommon symptoms for children with Anderson-Fabry Disease (FD) such as acroparaesthesia and gastrointestinal manifestations can only be objectively assessed in patients using a valid instrument. To date, no such instrument exists.MethodsA preliminary 40-item measure of symptoms and experience with FD, the Fabry-specific Paediatric Health and Pain Questionnaire (FPHPQ) was developed, but lacked a formal assessment of its measurement properties. The FPHPQ was used in the Fabry Outcome Survey (FOS), a registry for all patients with a confirmed diagnosis of FD who are receiving agalsidase alfa, or are treatment naïve and who are managed by physicians participating in FOS. After an item analysis to explore how items performed and combined into domains, a battery of psychometric analyses was performed to assess the measurement properties of this new instrument.ResultsEighty-seven children (ages 4-18 years) completed the questionnaire. Twenty-three items in three subscales of the questionnaire emerged: pain associated with heat or exertion, pain associated with cold, and abdominal pain and fatigue symptoms. Internal consistency reliability for all three subscales was good (Cronbach alpha ≥ 0.84). Reliability was equally high for all age groups (4-7, 8-12, and 13-18). Test-retest reliability was high for all three subscales (intraclass correlation coefficient ≥ 0.74). Construct validity was demonstrated by moderate correlation with brief pain inventory (BPI), KINDL, and EQ-5D. Known group validity showed all subscales were able to discriminate between Fabry disease severity groups as classified by above or below median of the FOS MSSI (Mainz Severity Score Index) grade. The heat or exertion subscale was responsive to change in symptoms between responders and non-responders as defined by change in EQ-5D index scores between the first and second visit.ConclusionsPreliminary results indicate that the measurement properties of FPHPQ are valid and reliable for assessing patient-reported symptoms of FD. The questionnaire could be a useful tool for clinicians to understand the progression of disease and monitor treatment effects. FPHPQ will be further validated and refined as the FOS registry is continuously adding more patients.
Highlights
Common symptoms for children with Anderson-Fabry Disease (FD) such as acroparaesthesia and gastrointestinal manifestations can only be objectively assessed in patients using a valid instrument
Out of the 299 children registered in Fabry Outcome Survey (FOS) at the cut-off time of this study, responses from 87 children that completed the questionnaire in eight of the countries were used for these analyses
Reliability, validity, and responsiveness The Cronbach alphas were 0.94, 0.85, and 0.85 for pain associated with heat or exertion, pain associated with cold, and abdominal pain and fatigue subscales, respectively, showing good internal consistency reliability across all age groups
Summary
Common symptoms for children with Anderson-Fabry Disease (FD) such as acroparaesthesia and gastrointestinal manifestations can only be objectively assessed in patients using a valid instrument. Anderson-Fabry disease (FD) is a rare condition, but the second most common among the lysosomal storage diseases (LSD) and the only X-linked sphingolipidosis [1,2] It is an inherited disorder caused by a deficiency of alpha-galactosidase A (GLA) that results in a slowly progressive disease with premature death in adult males and some females due to cardiac, renal or central-nervesystem (CNS) events [2]. Other symptoms may include fatigue, nausea, dizziness, gastrointestinal symptoms such as diarrhoea, a decreased ability to sweat, angiokeratoma, cornea verticillata and hearing impairment may occur in childhood
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
