title: 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.
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: rhpdemeel@lumc.nl.
authors.forename: Robert H P
authors.initials: RH
authors.lastname: de Meel
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: a.f.lipka@lumc.nl.
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Lipka
authors.affiliation: Department of Biostatistics, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: e.w.van_zwet@lumc.nl.
authors.forename: Erik W
authors.initials: EW
authors.lastname: van Zwet
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: e.h.niks@lumc.nl.
authors.forename: Erik H
authors.initials: EH
authors.lastname: Niks
authors.affiliation: Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands. Electronic address: j.j.g.m.verschuuren@lumc.nl.
authors.forename: Jan J G M
authors.initials: JJ
authors.lastname: Verschuuren
mesh_terms: D000328:Adult; D017677:Age Distribution; D004576:Electromyography; D004638:Emergency Treatment; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000175:diagnosis* / Q000276:immunology / Q000628:therapy*; D011379:Prognosis; D011950:Receptors, Cholinergic / Q000276:immunology; D012189:Retrospective Studies; D013934:Thymectomy
chemical_list: D011950:Receptors, Cholinergic
keywords: Course; Emergency treatment; Exacerbation; Late-onset MG; Myasthenia gravis; Prognosis