Prognostic factors for exacerbations and emergency treatments in myasthenia gravis

Abstract

Background: Disease course in myasthenia gravis (MG) patients is highly variable. Prognostic factors that identify patients at risk for a more severe disease course would be helpful in clinical practice.

Methods: We investigated MG patients under treatment at our university medical center between 1993 and 2013. The impact of baseline characteristics on the occurrence of exacerbations and the necessity of emergency treatments were investigated using multiple logistic regression analysis and log-rank tests for our Kaplan-Meier survival curves.

Results: We included 96 MG patients. Late age at onset (LOMG, ≥ 50 years) was associated with a higher risk of an exacerbation (odds ratio [OR]=9.33, 95% confidence interval [CI] = 2.43-35.87; p = 0.001) and the necessity of an emergency treatment within 3 years (OR = 5.25, 95% CI = 1.21-22.80; p = 0.027). The presence of additional autoimmune diseases (AID) in the patient was associated with a higher risk of an exacerbation (OR = 4.03, 95% CI = 1.09-14.85; p = 0.036). Patients with both LOMG and an additional AID had a markedly higher risk of an exacerbation (OR = 47.00, 95% CI = 6.49-340.65; p < 0.001) and the necessity of an emergency treatment (OR = 26.11, 95% CI = 4.12-165.55; p = 0.001) compared to early-onset patients without additional autoimmune diseases.

Conclusions: Late-onset MG and the presence of additional autoimmune diseases were associated with a higher risk of exacerbations of MG and the necessity of emergency treatments.

Keywords: Course; Emergency treatment; Exacerbation; Late-onset MG; Myasthenia gravis; Prognosis.