Health-Related Quality of Life in Patients with Spinocerebellar Ataxia: a Validation Study of the EQ-5D-3L
Maresa Buchholz, Niklas Weber, Anika Rädke, Jennifer Faber, Tanja Schmitz‐Hübsch, Heike Jacobi, Feng Xie, Thomas Klockgether, Bernhard Michalowsky, The EUROSCA study group, Sophie Tézenas du Montcel, Peter Bauer, Paola Giunti, Arron Cook, Robyn Labrum, Michael Parkinson, Alexandra Dürr, Alexis Brice, Perrine Charles, Cécilia Marelli, Caterina Mariotti, Lorenzo Nanetti, Marta Panzeri, Maria Rakowicz, Anna Sułek, Anna Sobańska, Lüdger Schöls, Holger Hengel, László Balikó, Béla Melegh, Alessandro Filla, Antonella Antenora, Jon Infante, José Berciano, Bart P.C. van de Warrenburg, Dagmar Timmann, Sandra Szymanski, Sylvia Boesch, Jun‐Suk Kang, Massimo Pandolfo, Jörg B. Schulz, Sonia Molho, Alhassane Diallo, The ESMI study group, Jeanette Hübener-Schmid, Magda M. Santana, Marcus Grobe‐Einsler, Berkan Koyak, Mafalda Raposo, Manuela Lima, Héctor García‐Moreno, Paola Giunti, Luís Pereira de Almeida, Bart van de Warrenburg, Judith van Gaalen, Dagmar Timmann, Andreas Thieme, Kathrin Reetz, Imis Dogan, Carlo Wilke, Lüdger Schöls, Olaf Rieß, Matthis Synofzik, Jeroen de Vries, Jon Infante, Oz Gulin, James M. Joers, Chiadikaobi Onyike, Michal Považan, Eva‐Maria Ratai, Jeremy D. Schmahmann
Abstract
Abstract Although health-related quality of life (HRQoL) has developed into a crucial outcome parameter in clinical research, evidence of the EQ-5D-3L validation performance is lacking in patients with spinocerebellar ataxia (SCA) types 1, 2, 3, and 6. The objective of this study is to assess the acceptability, validity, reliability, and responsiveness of the EQ-5D-3L. For n = 842 predominantly European SCA patients of two longitudinal cohort studies, the EQ-5D-3L, PHQ-9 (Patient Health Questionnaire), and ataxia-specific clinical assessments (SARA: Scale for Assessment and Rating of Ataxia; ADL: activities of daily living as part of Friedreich’s Ataxia Rating Scale; INAS: Inventory of Non-Ataxia Signs) were assessed at baseline and multiple annual follow-ups. The EQ-5D-3L was evaluated regarding acceptability, distribution properties, convergent and known-groups validity, test-retest reliability, and effect size measures to analyze health changes. The non-item response was low (EQ-5D-3L index: 0.8%; EQ-VAS: 3.4%). Ceiling effects occurred in 9.9% (EQ-5D-3L) and 3.0% (EQ-VAS) with a mean EQ-5D-3L index of 0.65 ± 0.21. In total, convergent validity showed moderate to strong Spearman’s rho ( r s > 0.3) coefficients comparing EQ-5D-3L and EQ-VAS with PHQ-9, SARA, ADL, and INAS. EQ-5D-3L could discriminate between groups of age, SARA, ADL, and INAS. Intra-class correlation coefficients (EQ-5D-3L ICC : 0.95/EQ-VAS ICC : 0.88) and Kappa statistics (range 0.44 to 0.93 for EQ-5D-3L items) indicated tolerable reliability. EQ-5D-3L shows small (effect size < 0.3) to moderate (effect size 0.3–0.59) health changes regarding ataxia severity. The analysis confirms an acceptable, reliable, valid, and responsive recommended EQ-5D-3L in SCA patients, measuring the HRQoL adequately, besides well-established clinical instruments.