Objective: To assess the prognosis of thymectomy in treatment of ocular myasthenia gravis (OMG) and relevant influencing factors.
Methods: A total of 135 OMG patients were included. The clinical course and the prognosis were reviewed in 65 patients with thymectomy and in 70 with medication. We compared the rate of relapse and conversion into generalized myasthenia gravis (GMG) between two different treatments for OMG by Kaplan-Meier analysis. An analysis of COX regression model was employed to compare gender, age, duration of pre thymectomy, acetylcholine receptor antibody (AChR Ab), anti-titin antibody (Titin Ab), thymus pathology and post thymectomy prednisone. The rates of relapse and conversion in OMG with thymomas or non-thymomas and with Titin Ab positive or negative after thymectomy were further investigated.
Results: The median follow-up was 62 months. The effective rate was 72.3% in the thymectomy group and 34.3% in the medication group (P < 0.01). The COX regression analysis revealed that the prognosis was statistically independent of Titin Ab (P < 0.05), thymus pathology (P < 0.05) and prednisone treatment (P < 0.05). The rate of relapse (Log-Rank, P < 0.05) and the rate of conversion (Log-Rank, P < 0.05) were smaller in the thymectomy group than in the medication groups. The rates of relapse and conversion in OMG with Titin Ab positive or thymomas were higher than OMG with Titin Ab negative or non-thymomas (Log-Rank, P < 0.05).
Conclusion: As an effective and safe treatment for OMG, thymectomy can relieve the symptoms and prevent the progression of OMG to GMG.