Longitudinal Analysis of Disease Burden in Refractory and Nonrefractory Generalized Myasthenia Gravis in the United States.

To compare temporal trends in clinical and health care resource utilization (HRU) outcomes in people with refractory and nonrefractory generalized myasthenia gravis (gMG). A retrospective analysis of data from adults with gMG in the Myasthenia Gravis Foundation of America Patient Registry. gMG status (ever-refractory or always nonrefractory) and clinical (Myasthenia Gravis-Activities of Daily Living [MG-ADL] scores, exacerbations) and HRU outcomes were determined from questionnaires self-completed 6-monthly for up to 4 years. The probability of each outcome was compared for the 2 groups over time. The mean MG-ADL score and the probability of experiencing each outcome were significantly greater in the ever-refractory versus nonrefractory groups during each year of follow-up. Between-group differences in time trends were statistically significant for intensive care and feeding-tube use. People who have ever had refractory gMG may have worse functional status, more exacerbations, and higher HRU than people with consistently nonrefractory disease.