title: The Val30Met familial amyloid polyneuropathy specific Rasch-built overall disability scale (FAP-RODS(©) ).
abstract: Familial amyloid polyneuropathy (FAP) is a chronic debilitating multi-organic disorder, mainly assessed using ordinal-based impairment measures. To date, no outcome measure at the activity and participation level has been constructed in FAP. The current study aimed to design an interval activity/participation scale for FAP through Rasch methodology. A preliminary FAP Rasch-built overall disability scale (pre-FAP-RODS) containing 146 activity/participation items was assessed twice (interval: 2-4 week; test-retest reliability) in 248 patients with Val30Met FAP examined in Porto, Portugal, of which 65.7% have received liver transplantation. An ordinal-based 24-item FAP-symptoms inventory questionnaire (FAP-SIQ) was also assessed (validity purposes). The pre-FAP-RODS and FAP-SIQ data were subjected to Rasch analyses. The pre-FAP-RODS did not meet model's expectations. On the basis of requirements such as misfit statistics, differential item functioning, and local dependency, items were systematically removed until a final 34-item FAP-RODS(©) was constructed fulfilling all Rasch requirements. Acceptable reliability/validity scores were demonstrated. In conclusion, the 34-item FAP-RODS(©) is a disease-specific interval measure suitable for detecting activity and participation restrictions in patients with FAP. The use of the FAP-RODS(©) is recommended for future international clinical trials in patients with Val30Met FAP determining its responsiveness and its cross-cultural validation. Its expansion to other forms of FAP should also be focus of future clinical studies.
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Mariëlle H J
authors.initials: MH
authors.lastname: Pruppers
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Neurology, Spaarne Hospital, Hoofddorp, The Netherlands.
authors.forename: Ingemar S J
authors.initials: IS
authors.lastname: Merkies
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Catharina G
authors.initials: CG
authors.lastname: Faber
authors.affiliation: Unidade Clinica de Paramiloidose, Hospital de Santo António, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Da Silva
authors.affiliation: Unidade Clinica de Paramiloidose, Hospital de Santo António, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Costa
authors.affiliation: Unidade Clinica de Paramiloidose, Hospital de Santo António, Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Coelho
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D028227:Amyloid Neuropathies, Familial / Q000235:genetics* / Q000503:physiopathology*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008715:Methionine / Q000235:genetics; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D017063:Outcome Assessment, Health Care; D011174:Portugal; D011228:Prealbumin / Q000235:genetics*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014633:Valine / Q000235:genetics
chemical_list: D011228:Prealbumin; D008715:Methionine; D014633:Valine
keywords: Rasch-built disability scale; activity and participation; familial amyloid polyneuropathy; outcome research; validity and reliability