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.

Quality of life outcomes in APOLLO, the phase 3 trial of the RNAi therapeutic patisiran in patients with hereditary transthyretin-mediated amyloidosis

“…Measure of QOL related to activities of daily living: R-ODS R-ODS measures activities of daily living and captures the ability of an individual to function independently in daily life [20,45]. The 24-item R-ODS measures limitations in usual daily activities and social participation [16,29,46].…”

“…This subsequently impacts the patients' abilities to complete everyday tasks, work and attend social functions. Among the disease symptoms, neuropathy manifests as pain, sensation loss, weakness and reduced mobility, and can significantly impair patients' abilities to perform activities of daily living such as buttoning a shirt or turning a key in a lock [20]. Autonomic dysfunction leads to orthostatic intolerance and debilitating GI symptoms that are associated with loss of consciousness and extreme constipation and diarrhea, respectively.…”

Content validity of symptom-based measures for diabetic, chemotherapy, and HIV peripheral neuropathy

“…One important example involves transthyretin familial amyloid polyneuropathy (TTR‐FAP) . The results of recent randomized clinical trials of tafamidis and diflunisal showed benefits in patients with TTR‐FAP on ClinRO and PRO measures, for example, the Norfolk QOL‐DN; in addition, Rasch‐built symptom and disability measures have been developed for use in future clinical trials . These recent studies of TTR‐FAP have the potential to be used as models to address challenging issues in clinical trial design and the development of novel PROs for disease‐modifying treatments for the peripheral neuropathies we have discussed.…”

Assessment of patients with hereditary transthyretin amyloidosis – understanding the impact of management and disease progression

“…Additionally, the Val30Met Familial Amyloid Polyneuropathy Specific Rasch-Built Overall Disability Scale (FAP-RODS) is a 34-item, disease-specific interval measure suitable for detecting activity and participation restrictions in patients with ATTRv amyloidosis [20].…”