Exploring outcomes and characteristics of myasthenia gravis: Rationale, aims and design of registry - The EXPLORE-MG registry

Objectives: Though much information exists about the diagnosis, treatment, and epidemiology of myasthenia gravis (MG), a comprehensive data registry and biorepository is critical to better understand disease mechanisms, treatment outcomes, and the impact of treatment strategies. We aimed to design and implement the "Exploring Outcomes and Characteristics of Myasthenia Gravis (EXPLORE-MG) Registry" to address these knowledge gaps. Methods: A web-based, non-interventional, longitudinal, observational disease and outcomes registry was developed; incorporating NIH recommended common data elements for the study of MG. Individuals diagnosed with MG based on prespecified criteria were eligible to participate. The registry was further strengthened by a complementary biorepository. An interim analysis was completed on registry data collected through data-lock in 2017. Results: A total of 232 MG patients, followed at the Yale MG Clinic from 2011 to 2017, were enrolled, which included 2142 total visit entries. Of the 232 MG patients (mean age 60 years, range 17-99; female:male, 1.04:1), 165 were acetylcholine receptor antibody-positive, 20 were muscle-specific kinase antibody-positive, and 47 were seronegative. This cohort consisted of 64 patients with ocular disease, 168 patients with generalized disease, and 65 patients post-thymectomy, including 20 with thymoma-associated MG. Conclusions: Identification of key clinical features that may predict treatment responsiveness or provide insight into patient outcomes is essential to improve patient care. As current research focuses on the development of patient-tailored, targeted-treatment regimens, this registry can help provide important clinical and epidemiological data from a large contemporary patient cohort with long-term follow-up.