Muscle strength and psychiatric symptoms influence health-related quality of life in patients with myasthenia gravis

•The frequency of anxiety is high in patients with myasthenia gravis.•Quality of life of patients with MG is impaired by skeletal muscle weakness.•Quality of life of patients with MG is impaired by psychiatric symptoms. Myasthenia gravis (MG) is a neuromuscular autoimmune disease characterized by skeletal muscle weakness which can impact motor function and, furthermore, produce negative impact on the health-related quality of life (HRQOL). Objective: To evaluate the predictors for HRQOL in patients with MG. Methods: Eighty patients were evaluated with the MG Foundation of America classification and the MG Composite scale. HRQOL was estimated by the MGQOL15, while anxious and depressive symptoms were evaluated with the Hospital Anxiety and Depression Scale (HAD). Results: The mean age of patients was 41.9 years with mean illness duration of 13.5 years. Almost half of the patients (43.75%) had significant anxiety and more than a quarter (27.50%) had depressive symptoms. Factors that influenced the HRQOL in MG were skeletal muscle weakness and anxiety and depressive symptoms (p