Validation of the italian version of the 15-item Myasthenia Gravis Quality-of-Life questionnaire

Introduction In this study we assess the Italian version of the 15-item Myasthenia Gravis Quality-of-Life questionnaire (MG-QOL15). Methods The validation protocol included the MG-QOL15, the 36-item Short Form (SF-36), the Besta Neurological Institute Rating Scale for Myasthenia Gravis, and the MG-Composite. We used the Cronbach α to test reliability, the Spearman correlation to test short-term test–retest, the Kruskal–Wallis test to assess differences in MG-QOL15 between patients with different disease severity, and the Wilcoxon signed-rank test to assess sensitivity to change. Results Seventy-two patients were enrolled in the study. The mean MG-QOL15 score was 15.2 ± 12.2, with α = 0.93 and test–retest correlation = 0.93. Compared with the SF-36, the MG-QOL15 was superior in differentiating patients with different MG types (P = 0.041) and severity (P = 0.004), showed higher sensitivity to change (P = 0.003 for improved and P = 0.024 for worsened patients), and had higher correlations with the MG-Composite (rho = 0.367 vs. –0.213 and –0.154). Conclusion The Italian version of the MG-QOL15 is valid, reliable, stable, and sensitive to changes. Muscle Nerve 56: 716–720, 2017