Subgroup stratification and outcome in recently diagnosed generalized myasthenia gravis
Matthias Tomschik, Eva Hilger, Jakob Rath, Eva-Maria Mayer, Michael Fahrner, Hakan Çetin, Wolfgang N. Löscher, Fritz Zimprich
Abstract
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 disease onset after the year 2000 who were treated at 2 tertiary referral centers in Austria. We stratified patients as early- and late-onset acetylcholine receptor antibody-positive, muscle-specific tyrosine kinase (MuSK) antibody-positive, and seronegative patients and patients with thymoma regardless of antibody status. We evaluated patients' symptom severity and treatment regimens and the occurrence of life-threatening events at yearly time points for up to 10 years. RESULTS: Minimal manifestation status or better was eventually achieved and sustained for >1 year by 125 (63%) patients. Forty percent (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 2 years after disease onset despite immunosuppressive therapy, were more treatment resistant in the following years. The strongest predictor of outcome was the diagnostic subgroup. Patients with MuSK-MG had a much better outcome than previously reported. CONCLUSION: Our data give an update on the disease course of generalized MG in the new century. Diagnostic subgroups and response to treatment within the first 2 years help to predict the long term outcome.