Introduction: Our objective in this study was to assess the psychometric properties of the English (UK and USA) version of the Pediatric Quality of Life Inventory 3.0 Neuromuscular Module (PedsQL NMM) administered to patients with Duchenne muscular dystrophy (DMD).
Methods: Patients with DMD from the UK and the US completed the PedsQL NMM online. The psychometric properties of the instrument were examined using Rasch analysis.
Results: A total of 278 patients completed the PedsQL NMM. Model misfit was identified for 6 of 25 items (item fit residual: mean 0.162, standard deviation [SD] 2.333), 22 of 25 items displayed disordered thresholds, and item dependency was high. The mean person fit residual was estimated at -0.183 (SD 1.475). The Person Separation Index and Cronbach's α were estimated at 0.904 and 0.915, respectively.
Discussion: The English version of the PedsQL NMM may not be a valid measure of health-related quality of life in patients with DMD. Muscle Nerve 58: 367-373, 2018.
Keywords: DMD; PedsQL; Rasch analysis; psychometric analysis; rare disease; rating scale.
© 2018 Wiley Periodicals, Inc.