CLINICAL CHARACTERISTICS AND HEALTH STATE UTILITIES IN PATIENTS WITH TRANSTHYRETIN FAMILIAL AMYLOID POLYNEUROPATHY IN BRAZIL

• Published in: Value in health 2017-05, Vol.20 (5), p.A223
• Main Authors: Stewart, M, Mundayat, R, Alvir, J, Grima, D, Tran, D, Ong, M, Rill, D
• Format: Article
• Language: English
• Subjects: Amyloidosis; Clinical assessment; Clinical trials; Cost analysis; Data processing; Derivation; Disease; Health status; Medical treatment; Mutation; Neurological complications; Neuropathology; Patients; Polyneuropathy; Quality of life; Rare diseases; Tariffs; Transthyretin
• ISSN: 1098-3015; 1524-4733
• DOI: 10.1016/j.jval.2017.05.005

OBJECTIVES: To obtain clinical characteristics and quality of life data using an international rare disease registry to inform development of a cost-effectiveness model for treatment of transthyretin familial amyloid polyneuropathy (TTR-FAP) in Brazil. METHODS: A retrospective analysis of data from the ongoing, international Transthyretin Amyloidosis Outcomes Survey (THAOS), a rare disease registry for transthyretin amyloidosis, was conducted (cut-off date: January 14, 2016). Descriptive analyses were performed on subject data collected during clinical evaluations using a variety of standard assessments, including a neurological examination that allows derivation of a Neurological Impairment Score-Lower Limb (NIS-LL), ambulatory status (for disease staging), and patient-reported health status (EQ-5D-3L). RESULTS: An overall total of 1,205 symptomatic subjects were included, most with the Val30Met mutation (N=970). Data were available for 93 Brazilian subjects, the majority of whom had the Val30Met mutation (N=88). Derived NIS-LL scores increased (worsened) with longer disease duration. For the transitions between the three Coutinho-based disease stages, cut-offs for the derived NIS-LL scores were established using the 25th and 75th percentiles of the second stage (46 and 63, respectively). Similar to the overall sample, Brazilian subjects with the Val30Met mutation were primarily in stage 1 (N=55, 71%) with fewer subjects in stages 2 (N=15, 19%) and 3 (N=8, 10%). EQ-5D-3L health state utilities calculated with Brazilian tariffs showed similar decrements with advancing stage in the Val30Met mutation group [mean (SD); stage 1: 0.70 (0.19), stage 2: 0.44 (0.18), and stage 3: 0.10 (0.20)] and other mutations group [stage 1: 0.68 (0.21), stage 2: 0.40 (0.16), and stage 3: 0.05 (0.11)]. CONCLUSIONS: Brazilian TTR-FAP subjects are similar to the overall THAOS registry cohort and exhibit lower quality of life as the disease worsens. Global disease registries such as THAOS play an important role in characterizing health status in rare diseases like TTR-FAP.