Outcome Predictors of Generalized Myasthenia Gravis: A Prospective Observational Study

Abstract

Background and Objectives: There is paucity of studies on long‑term remission of autoimmune generalized myasthenia gravis (MG) from Southeast Asia. We report the outcome predictors of generalized MG and also evaluate the influence of high‑ versus low‑dose prednisolone and prednisolone with or without azathioprine (AZA). Methods: Fifty‑seven patients with generalized MG were included, who completed 2 years of follow‑up. Demographic information, comorbidities, Myasthenia Gravis Foundation of America (MGFA) class at baseline and follow‑up, acetylcholine receptor (AChR) and muscle‑specific kinase antibodies, decremental response, thymectomy, and treatments were recorded. Maximum doses of prednisolone, AZA, and acetylcholinesterase inhibitors were noted. The predictors of MGFA 0 at 3 and 6 months and minimal manifestation (MM) status at 2 years were evaluated. Results: MGFA 0 was achieved by 27 (47.4%) patients at 3 months, 35 (61.4%) patients at 6 months, and 46 (80.7%) patients at 12 months. At 2 years, 48 (84.2%) patients achieved the MM status and none achieved complete stable or pharmacologic remission. On multivariate analysis, AChR antibody titer (adjusted odds ratio [AOR] 1.08, 95% confidence interval [CI] 1.006–1.167; P = 0.03) and MG activity of daily living (MGADL) at 6 months (AOR 1.28, 95% CI 1.066–1.558; P = 0.01) predicted the MM status. Maximum dose of prednisolone and adjunctive AZA did not predict the MM status. Conclusions: About 84.2% of patients with generalized MG, especially those with a low AChR antibody titer and MGADL < 4 at 6 months, achieved the MM status at 2 years.