Prevalence and risk factors of myasthenia gravis recurrence post-thymectomy.

OBJECTIVES

To evaluate the prevalence and the factors associated with recurrence of myasthenia gravis following thymectomy.

METHODS

Six electronic databases which reported on recurrence of myasthenia gravis following thymectomy and/or its risk factors from 1985 to 2018 were searched. Summary prevalence and risk values obtained based on the random effect models were reported.

RESULTS

Seventy (70) papers containing 7,287 individuals with myasthenia gravis who received thymectomy as part of their management were retrieved. The patients had a mean follow-up of 4.65 years post-thymectomy. The prevalence of myasthenia gravis recurrence post-thymectomy was 18.0% (95% CI 14.7-22.0%; 1865/7287). Evident heterogeneity was observed (I2=93.6%; p<0.001). Recurrence rate was insignificantly higher in male compared with female patients (31.3 vs. 23.8%; p=0.104). Pooled recurrence rates for thymomatous (33.3%) was higher than the rate among non-thymomatous (20.8%) myasthenia gravis patients (Q=4.19, p=0.041). Risk factors for recurrence include older age, male sex, disease severity, having thymomatous myasthenia gravis, longer duration of the myasthenia gravis before surgery, and having an ectopic thymic tissue.

CONCLUSION

A fifth of individuals with myasthenia gravis experience recurrence after thymectomy. Closer monitoring should be given to at-risk patients and further studies are needed to understand interventions to address these risks.