The aims were to determine the impact of dysphagia and glomerular filtration rate (GFR) in the prediction of myasthenia relapse and analyse whether different number of plasma exchange sessions could prolong the time before future relapse.This was a retrospective, longitudinal follow-up study with 60 enrolled patients. The patients were followed-up for a total of 50 months.Patients without relapses had significantly higher GFR and higher number of plasma exchange sessions when compared to patients with relapses. Mean time before next myasthenia relapse was significantly longer in patients with GFR ≥ 60 mL/min. Time before next and number of following myasthenia relapses were significantly higher in patients with symptoms of dysphagia.Decline in GFR levels is strongly associated with the presence of dysphagia and independently impacts the onset of myasthenia relapses. Timely initiation of plasmapheresis therapy and adequate hydration of patients with prolonged dysphagia should be one of the treatment goals for clinicians treating this disease.