Myasthenia gravis: Classification and outcome measurements

Myasthenia gravis (MG) is the best characterized and understood autoimmune disease of the nervous system (Vincent et al., Lancet 357:2122-8, 2001). It is the most common neuromuscular transmission disorder followed in neurology clinics. Nevertheless, standardized classification and grading systems and outcome measures for MG were not developed until the 1990s and continue to be refined. In 1997, the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America (MGFA) formed a task force to design classification and outcome measures for the disease (Barohn, Ann N Y Acad Sci 998:432-9, 2003). The task force’s primary charge was to create a system of uniformity in recording and reporting clinical data and outcomes research. Chairing the project was Dr. Alfred Jaretzki III, a cardiothoracic surgeon who had published extensively with colleagues at the Columbia-Presbyterian Medical Center on thymectomy for MG (Jaretzki, Neurology 48:S52-63, 1997; Jaretzki et al., J Thorac Cardiovasc Surg 95:747-57, 1988). He expressed concern that published outcomes following thymectomy could not be reliably compared across studies due to the lack of universally accepted measures. It was soon recognized that essentially all MG clinical research suffered from this same dilemma. After 3 years of regular meetings, literature reviews, and input from MG experts, a consensus document on recommendations for MG clinical research standards was published in 2000 (Jaretzki et al., Neurology 55:16-23, 2000). Recommendations were updated in 2012 by a second MGFA-supported task force that included several members from the original panel (Benatar et al., Muscle Nerve 45:909-17, 2012).