Refractory status in Myasthenia Gravis (MG) remains difficult to determine, as each set of criteria has variable levels of specificity. The current lenient definition can result in unnecessary escalation of MG treatment, increasing both risks and costs for patients to endure. In addition, disease severity and quality of life (QoL) measures are often excluded in this discussion.

We applied the definitions of 5 refractory MG criteria (International Consensus Guideline (ICG), Regain, Drachman, Mantegazza, and Suh) to our MG population. 237 patient charts were reviewed for criteria eligibility and Chi-squared tests were used to compare the refractory proportions between criteria groups. We also studied the relationship between disease severity, fatigue, and QoL across the groups.

ICG and Regain refractory definitions were more conservative and reflective of treatment-refractory MG, having a proportion of 9.70% and 2.75% respectively. Patients within these two groups had higher disease severity and fatigue compared to other refractory definitions.

Our study demonstrated that the proportion of truly refractory MG should be under 10% and that disease severity and QoL should be considered in defining refractory status. Lastly, refractory status should not be considered permanent. Over time, tolerance to medication may change, and therefore refractory status.