Psychometric Properties of Preference-Based Measures for Economic Evaluation in Amyotrophic Lateral Sclerosis: A Systematic Review

OBJECTIVE: The aim of this review was to synthesize the psychometric properties of generic preference-based measures (PBMs) of health-related quality of life (HRQL) in Amyotrophic Lateral Sclerosis (ALS). METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four databases were searched from inception to April 2019: OVID Medline, Embase, PsycINFO, and CINAHL. Studies were included if (1) the sample represented individuals with ALS, (2) a generic PBM was utilized and reported on, and (3) information on the psychometric property of a generic PBM was provided. RESULTS: Ninety-one articles were screened, and 39 full-text articles were reviewed. Seven full-text articles were included in this review. The mean age of participants ranged from 58.1 to 63.8 years, and mean time since diagnosis ranged from 20.5 to 44.6 months. Two generic PBMs were found, the EQ-5D-3L (n = 6) and the Quality of Well-Being Self-Administered (QWB-SA) scale (n = 1). Convergent validity of the EQ-5D-3L was large against a global scale of self-perceived health (r = 0.60) and small to large against ALS specific HRQL measures (r = 0.19 to 0.75). For the QWB-SA scale, correlations were small against a generic measure (r = 0.21) and large against ALS specific measures (r = 0.55). The EQ-5D-3L discriminated across different disease severity; however, floor effects were reported. CONCLUSION: This review highlights the need for more rigorously designed studies to assess the psychometric properties of generic PBMs in ALS and the development of an ALS specific PBM that adequately reflects the health concerns of individuals with ALS.