Subgroup Stratification and Outcome in Recently Diagnosed Generalized Myasthenia Gravis.

Objective: To describe disease outcomes of myasthenia gravis (MG) subgroups and which factors influence outcomes by reviewing individual patient records of a representative cohort. Methods: We performed a retrospective analysis of 199 patients with generalized MG and a disease onset after the year 2000, who were treated at two tertiary referral centers in Austria. We stratified patients into early and late onset AChR-ab positive, MuSK-ab positive, seronegative patients and patients with thymoma regardless of antibody status. We evaluated patients’ symptom severity, treatment regimens and occurrence of life threatening events at yearly time points for up to ten years. Results: Minimal manifestation status or better was eventually achieved and sustained for longer than one year by 125 (63%) patients. 40% (66 of 165 patients) showed an early response to treatment, which predicted a benign disease course later on. In contrast, 19% of patients, who remained symptomatic for two years after disease onset despite immunosuppressive therapy, were more treatment resistant in the following years. The strongest predictor of outcome was the diagnostic subgroup. MuSK-MG had a much better outcome than previously reported. Conclusion: Our data give an update on the disease course of generalized myasthenia gravis in the new century. Diagnostic subgroups and response to treatment within the first two years help to predict the long term outcome.