Treatment strategies and treatment-related adverse events in MG according to the age of onset.

Introduction: Early-onset (EOMG) and late-onset (LOMG) are distinct groups of MG patients. It is unclear if treatment strategies and treatment-related adverse events may differ according to the age of MG onset.

Methods: This single-center retrospective study includes all MG patients followed at a tertiary center since 2007. We reviewed the electronic clinical records.

Results: In total, 212 patients were identified, 142 (67.0%) females, with a median disease duration of 10 years. The median age of symptom onset was 42.0 (26.0-64.5) years, with 130 (61.3%) EOMG cases and 82 (38.7%) LOMG. EOMG were more frequently female, had longer disease duration and often more generalized MG ( < 0.001). Comorbidities were significantly more frequent in LOMG (67.1%) compared to EOMG (53.1%) ( = 0.002). Steroid-related adverse effects motivating the switch to steroid-sparing agents (82.0%) were different between groups, with hypertension, hypercholesterolemia, diabetes mellitus and malignancies being more common in LOMG. At the same time, osteoporosis and dyspepsia were more frequent in EOMG ( < 0.001). The most common first-line choice was azathioprine (45.8%), and rituximab was used in 4 patients (1.9%).

Conclusion: Our study shows that treatment modalities are similar between EOMG and LOMG, while steroid-related adverse events appear to be distinct.