Myasthenia Gravis: Classification and Outcome Measurements

Myasthenia gravis (MG) is a well-characterized autoimmune disorder of the neuromuscular junction, yet standardized approaches to classification and outcome measurement have evolved relatively recently. Efforts led by the Myasthenia Gravis Foundation of America (MGFA) since the late 1990s have established widely adopted systems to improve consistency in clinical research and practice. The MGFA Clinical Classification provides a framework for categorizing disease severity, while multiple validated outcome measures capture distinct dimensions of disease status, including objective impairment, patient-reported symptoms, and quality of life. The Quantitative Myasthenia Gravis (QMG) score remains the most extensively studied objective measure, demonstrating strong reliability, responsiveness, and longitudinal validity. Complementary tools such as the Myasthenia Gravis Activities of Daily Living (MG-ADL) profile and the Myasthenia Gravis Composite (MGC) integrate patient-reported and clinician-assessed elements, offering efficient and clinically meaningful assessments of disease burden. Additional instruments, including the MG-QOL15R and MG Impairment Index, further incorporate patient perspective and functional impact. Despite these advances, variability in measurement performance and interpretation persists, underscoring the need for continued refinement and standardization. Recent initiatives, including MGNet recommendations, aim to harmonize application across clinical trials and practice. Together, these tools provide a multidimensional framework essential for evaluating therapeutic efficacy and guiding management in MG.