Outcome Predictors of Generalized Myasthenia Gravis: A Prospective Observational Study

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).

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.

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.

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.