Prognosis of myasthenia gravis: a multicenter follow-up study of 844 patients

The prognosis of myasthenia gravis (MG) was assessed retrospectively using life-table analysis in 844 patients followed up for a mean period of 5 years in 3 major Italian centers. The chance of achieving at least a 1-year remission after treatment withdrawal (complete remission) was assessed as a specific end-point in the whole population and in selected subgroups with reference to the principal prognostic variables. The cumulative probability of complete remission was 1% by 1 year, 8% by 3 years, 13% by 5 years, and 21% by 10 years. The only variables correlated to the chance of complete remission were younger age at onset of MG, lower severity of symptoms at onset and nadir, and shorter disease duration at diagnosis. In addition, thymectomy and early surgery seemed to influence the chance of remission. Other factors (including the presence of thymoma) did not significantly influence the outcome of the disease.