Less is not necessarily more: low-dose corticosteroid therapy and long-term prognosis in generalized myasthenia gravis after thymectomy

Objective We investigated the efficacy of low-dose prednisolone (PSL) regimen in patients with generalized myasthenia gravis (MG) post-thymectomy and its correlation with long-term outcome. Methods This is a 2-year observational study. The subjects were aged 16-75 years, a Myasthenia Gravis Foundation of America (MGFA) clinical classification of II to IV, generalized MG after thymectomy. We selected a low-dose (5 mg/day) initiation and slowly incrementing (10 mg every 4 weeks) PSL therapy regimen. We collected the clinical characteristics, treatment-related data, and 2-year clinical outcomes of MG patients, and analyzed the effect of various factors on the achievement of the treatment target. Results Sixty-three generalized MG were recruited in our study. After 2 years of observation, 52 patients (82.5%) of generalized MG achieved treatment goal. Based on the maximum daily dose of PSL received, the MG patients were divided into 20 mg, 30 mg, and >= 40 mg groups. Subgroup analysis showed that the 20 mg group had the highest rate of achieving the treatment target (94.9%), followed by the 30 mg group (73.3%) and the lowest rate was among the >= 40 mg group (44.4%). Using a multivariate logistic regression analysis, we identified that the maximum daily dose of PSL 20 mg was the only positive, independent predictor of treatment goal achievement after 2 years. Conclusion Low-dose initiation, slowly incrementing PSL therapy is feasible for generalized MG patients after thymectomy. Early response to low-dose PSL therapy may predict better long-term outcomes.