Prognostic factors of remission in myasthenia gravis after thymectomy

Thymectomy has become an increasingly popular procedure for myasthenia gravis. Knowledge of factors associated with a good outcome (remission) or those most likely to benefit from surgery can help clinical decision-making. A systematic review search was conducted in Medline and Embase for English language studies from 1985 through to February 2014. Studies which evaluated variables associated with, or predictive of, remission in adult (≥18 years) myasthenic patients after thymectomy and using multivariable regression models were included. Statistical pooling was not appropriate due to methodological heterogeneity. From 128 potentially relevant studies, 18 reports of 19 studies met the inclusion criteria. Preoperative mild disease classification (i.e. studies reported this variable as Osserman classification 1, 2A or MGFA I-II) showed the most consistent association with remission. Evidence for several other prognostic factors was inconclusive, or no evidence was found. Gender, age and absence of thymoma (or hyperplasia) were not associated with remission following thymectomy. Patients with mild disease preoperatively may have a better chance of remission of MG after thymectomy.