Data for 3,516 patients with MG were identified (51.2% male; mean age [standard deviation], 55.8 [13.9]; age range, 18–84 years). The most prevalent comorbidities were cardiovascular and endocrine disorders, including hypertension (41.9%), hyperlipidemia (37.1%), fatigue (24.8%), uncomplicated diabetes (18.2%), cerebrovascular disease (17.6%) and hypothyroidism (15.4%). Chronic pulmonary disease (13.5%) and sleep disorders (13.2%) were also common comorbidities. Patients were often prescribed conventional MG therapies, which have the potential exacerbate their comorbid conditions. Within 1 year prior to initiation of corticosteroids, 42.7%, 18.6% and 8.6% of patients were diagnosed with hypertension, uncomplicated diabetes and osteoporosis, respectively. Similarly, 6.5% of patients prescribed chronic intravenous immunoglobulin and 14.3% of patients prescribed azathioprine were diagnosed with venous thromboembolism and malignancy, respectively, within 1 year prior to treatment initiation.