A new study published in Neurology has shed new light on how age at disease onset influences symptoms, treatment response and long-term outcomes in myasthenia gravis (MG). The authors concluded that late-onset MG had the poorest prognosis.
Researchers reviewed medical records from more than 2,500 people treated for MG at three major hospitals in China over a 10-year period. They categorized the study participants into three categories based on when their symptoms began: juvenile MG (onset before age 18), early-onset MG (18 to 49) and late-onset MG (50 and older). They then compared symptoms, response to treatment and how long it took patients to reach “minimal-manifestation” status, meaning symptoms are mostly under control.
Those under 18 made up the largest share of patients in the study. Most children developed symptoms between infancy and age four, and more than 90% presented with eye-related muscle weakness. Although those with juvenile MG generally responded well to treatment, the study identified major risk factors for symptoms spreading beyond the eyes, including an enlarged thymus gland, the presence of acetylcholine receptor antibodies and the development of MG around puberty.
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Among adults, it was more common for people to develop MG after age 50 than before. This older group tended to include more men and had significantly higher rates of comorbidities, including hypertension, diabetes and coronary artery disease, which can make MG harder to manage. “Comorbidities are very common in older patients with MG and increase with age,” the study’s authors noted.
Older patients were less likely to reach minimal-manifestation status, with a rate of 66.7% compared with 74.7% of early-onset patients.
Across all ages, the study showed that certain factors, such as having generalized MG instead of just eye symptoms or having thymus problems, were associated with poorer long-term outcomes.
The study’s authors say the results underscore the need for age-specific strategies in MG care. Children entering puberty and older adults with multiple health issues may require closer monitoring and more individualized treatment plans to improve their chances of achieving disease control.
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