Thymectomy reduces severity of myasthenia gravis
Treatment with thymectomy improved clinical outcomes in patients with nonthymomatous myasthenia gravis over a 3-year period, a recent study found.
Despite being a common procedure in the treatment of myasthenia gravis, no conclusive evidence of thymectomy’s benefits has been established. To bridge this gap, researchers conducted a multicenter, randomized trial comparing thymectomy plus prednisone with prednisone alone.
The study included 126 patients (aged 18 to 65 years) who had generalised nonthymomatous myasthenia gravis with a disease duration of less than 5 years, class II to IV disease based on the Myasthenia Gravis Foundation of America clinical class, and an elevated circulating concentration of acetylcholine-receptor antibody.
The primary outcomes were the time-weighted average Quantitative Myasthenia Gravis (QMG) score (on a scale from 0 to 39, with higher scores indicating more severe disease) over a 3-year period, and the time-weighted average required dose of prednisone over a 3-year period.
Patients who underwent thymectomy had a lower time-weighted average QMG score over a 3-year period than those who received prednisone alone (6.15 vs 8.99; p<0.001). The same individuals also had a lower average requirement for alternate-day prednisone (44 vs 60 mg; p<0.001).
There were fewer patients in the thymectomy group than in the prednisone-only group that needed immunosuppression with azathioprine (17 vs 48 percent; p<0.001) or were hospitalised for exacerbations (9 vs 37 percent; p<0.001).
“This trial provides evidence supporting the use of thymectomy for improving clinical outcomes and reducing the need for immunosuppressive therapy in patients with myasthenia gravis,” researcher said.
The number of patients with treatment-associated complications did not differ significantly between groups (p=0.73), but patients in the thymectomy group had fewer treatment-associated symptoms related to immunosuppressive medications (p<0.001) and lower distress levels related to symptoms (p=0.003).
Some limitations of the study included its single-blind nature and the pill-count method, researchers noted.