Clinical characteristics of patients with myasthenia gravis associated with other autoimmune diseases

Abstract

Objective To analyze the clinical characteristics, drug efficacy and prognosis of patients with myasthenia gravis (MG) associated with other autoimmune diseases. Methods Eighty-three MG patients were divided into 2 groups. One group included MG patients with autoimmune diseases (AIDMG, N = 24), and the other included MG patients without autoimmune diseases (NAIDMG, N = 59). Firstly, clinical features such as sex, age of onset, initial symptoms and thymus abnormalities were compared between patients with AIDMG and NAIDMG. Secondly, effect of different therapies, including pyridostigmine, corticosteroids, immunoglobulin, immunosuppressants and thymectomy was compared between 2 groups. Finally, prognosis including relapse rate and recurrence time during the first 2 years after MG onset was compared. Whether and when ocular myasthenia gravis (OMG) progressing to general myasthenia gravis (GMG) and the first onset of GMG symptoms during the first 2 years were also compared between 2 groups.  Results The difference of gender predominance (χ² = 8.467, P = 0.004), ptosis affecting left or right or both sides (χ² = 9.830, P = 0.007) and disease course within 2 years after onset (χ² = 15.255, P = 0.001) between AIDMG group and NAIDMG group were statistically significant. Other clinical features such as age of onset (χ² = 1.728, P = 0.228), initial symptoms (χ² = 0.252, P = 0.791), thymus abnormalities (χ² = 3.200, P = 0.202) were not significantly different between 2 groups. Differences of therapeutical effect such as pyridostigmine (χ² = 0.411, P = 0.395), corticosteroids (χ² = 0.156, P = 0.513), immunoglobulin (χ² = 0.359, P = 0.462), immunosuppressants (χ² = 0.081, P = 0.526) and thymectomy (χ² = 0.337, P = 0.391) between 2 groups were not statistically significant. The ratio of OMG progressing to GMG (χ² = 1.826, P = 0.148), time of progressing (Fisher's exact test: P = 0.639), first onset symptom (Fisher's exact test: P = 0.196) and recurrence time (Fisher's exact test: P = 1.000) were not significantly different between 2 groups. Conclusions AIDMG was more common in female patients. Bilateral ptosis involvement at the same time was more common in AIDMG. Relapse rate during the first 2 years after MG onset was higher in AIDMG than that in NAIDMG.

doi: 10.3969/j.issn.1672-6731.2014.10.009