Concordance between severity of disease, disability and health-related quality of life in myasthenia gravis.

Aim of this study is to verify whether there is concordance between disease's severity, health-related quality of life (HRQoL) and disability in patients with myasthenia gravis (MG). 102 MG patients were clustered on the basis of HRQoL and disability scores into three groups: low disability and low HRQoL decrement (51 patients), intermediate disability and HRQoL decrement (28 patients), severe disability and high HRQoL decrement (23 patients). Cross tabulation with symmetric measures (Cramer's V and Contingency Coefficient) was used to verify the relationships between disease severity groups, based on the Myasthenia Gravis Foundation of America (MGFA) criteria, and obtained clusters. Results confirm a significant relationship between MG severity groups, HRQoL and disability profiles. In our opinion, HRQoL and disability instruments should be employed in clinical trials to match efficacy of treatments, measured on symptoms' reductions only, with their effects on patients' disability and HRQoL.