Patients with myasthenia gravis often experience fatigue, but its effect on quality of life (QoL) is underestimated, and fatigue is rarely measured in clinical trials.

Two hundred fifty-seven myasthenic patients completed the Neuro-QoL-Fatigue and measures of disease severity and QoL. We studied the relationship between fatigue and clinical and demographic variables. Finally, we studied the responsiveness of the Neuro-QoL-Fatigue in 95 patients receiving treatments for myasthenia and estimated the minimal important difference (MID).

Fatigue correlated with greater disease severity (r = 0.52-0.69, P < 0.0001) and worse QoL (r = 0.65-0.75, P < 0.0001). Patients in remission, with minimal manifestations, and pure ocular symptoms reported minimal fatigue. Regression modeling showed that, in addition to its relationship with disease severity, fatigue was worse in females, patients with generalized disease, and those with anxiety/depression. Fatigue improved after immunomodulation (P < 0.0001), and the MID was 5.3 points.

Fatigue in myasthenia correlates with disease severity, affects QoL, and can improve after treatment. Muscle Nerve 58: 197-203, 2018.