Myasthenia gravis: correlation of age with clinical course and anti-AChr antibody levels.

: We studied the significance of age as a factor affecting prognosis and anti-AChR antibody levels in myasthenia gravis, comparing patients with symptom onset before 50 (37 patients) and at or after 50 (33 patients). More of the older patients, compared to younger ones (69.9% versus 32.4%,p<0. 05) progressed to severe disease in the first three years of treatment. Five older patients died during myasthenic crises, whereas no deaths occured in the younger group. In addition; older patients did not respond as favorably as younger ones to anticholinesterase treatment and more of them required combination therapy. AntiAChR antibody levels were significantly lower in older patients (9.2 versus 34.9 nM, p<0.005). We conclude that symptom onset at or after the age of 50 predicts unfavorable outcome in myasthenia gravis and is associated with lower anti-AChR antibody levels. This group of patients requires earlier treatment with corticosteroids, immunosuppressive drugs or both.