Clinical and therapeutic features of myasthenia gravis in adults based on age at onset

Abstract

ObjectiveTo describe the characteristics of patients with very-late-onset myasthenia gravis (MG).MethodsThis observational cross-sectional multicenter study was based on information in the neurologist-driven Spanish Registry of Neuromuscular Diseases (NMD-ES). All patients were >18 years of age at onset of MG and onset occurred between 2000 and 2016 in all cases. Patients were classified into 3 age subgroups: early-onset MG (age at onset <50 years), late-onset MG (onset ≥50 and <65 years), and very-late-onset MG (onset ≥65 years). Demographic, immunologic, clinical, and therapeutic data were reviewed.ResultsA total of 939 patients from 15 hospitals were included: 288 (30.7%) had early-onset MG, 227 (24.2%) late-onset MG, and 424 (45.2%) very-late-onset MG. The mean follow-up was 9.1 years (SD 4.3). Patients with late onset and very late onset were more frequently men (p < 0.0001). Compared to the early-onset and late-onset groups, in the very-late-onset group, the presence of anti–acetylcholine receptor (anti-AChR) antibodies (p < 0.0001) was higher and fewer patients had thymoma (p < 0.0001). Late-onset MG and very-late-onset MG groups more frequently had ocular MG, both at onset (<0.0001) and at maximal worsening (p = 0.001). Although the very-late-onset group presented more life-threatening events (Myasthenia Gravis Foundation of America IVB and V) at onset (p = 0.002), they required fewer drugs (p < 0.0001) and were less frequently drug-refractory (p < 0.0001).ConclusionsPatients with MG are primarily ≥65 years of age with anti-AChR antibodies and no thymoma. Although patients with very-late-onset MG may present life-threatening events at onset, they achieve a good outcome with fewer immunosuppressants when diagnosed and treated properly.

The Duke myasthenia gravis clinic registry: I. Description and demographics

“…Increasing age of the MG population has been documented in several recent reports 32‐35 . This is also seen in the Registry population, in which an increasing proportion of males over three decades is accompanied by increasing overall onset age and an increasing proportion of patients with LOMG.…”

“…Thus, it is not surprising that the distribution of Maximum MGFA Class varies considerably among recently‐reported series (Supporting Information Figure S2). 35,49 …”

“… Figure S2. Number of patients in each Maximum MGFA Class among 1037 Registry cohort patients and two recently‐reported series 35,49 …”

Human Leukocyte Antigen Class II associations in late‐onset Myasthenia Gravis

“…1 AChR MG includes three clinical subtypes: early-onset MG (EOMG), late-onset MG (LOMG), generally defined by a cut-off age of 50 years, and thymoma-associated MG. 2 While EOMG epidemiology has not changed over time, the incidence and prevalence rates of LOMG have steadily increased in the last decades. [3][4][5][6] Given the aging of the general population, it is predictable that LOMG will be even more prevalent in the near future.…”

Histopathologic study of extraocular muscles in thyroid-associated ophthalmopathy coexisting with ocular myasthenia gravis: a case report

“…MG is an autoimmune condition characterized by the symptom of muscle weakness which results from autoantibodies to neuromuscular junctions. Patients with symptoms confined to ocular muscles are classified as ocular MG (OMG) [3]. Approximately 15.0% of MG patients have a concurrent autoimmune disease, but co-occurrence of TAO and OMG is very rare [4].…”