Understanding Racial and Ethnic Disparities in Myasthenia Gravis Outcomes: EXPLORE-MG Registry Experience

Abstract

Background and ObjectivesPast studies have reported racial and ethnic differences in patients with myasthenia gravis (MG) but either are over a decade old or only examine small samples. To better understand these differences, using the EXPLORE-MG registry, we conducted a retrospective cohort study of racial and ethnic differences in the characteristics and long-term outcomes of patients with MG.MethodsPatients with a diagnosis of MG confirmed by one or more of the assessments such as antibody seropositivity, positive single-fiber electromyography, or decremental repetitive nerve stimulation between January 2001 and October 2023 were included in the analysis. For logistic regression models, we performed a complete case analysis, therefore excluding patients with unknown age at onset or history of thymoma. Only patients with 2 years of follow-up data were included in the long-term outcome analysis.ResultsOf 594 study participants, the clinical features of 473 White, 48 African American (AA), 42 Hispanic, and 523 non-Hispanic patients were compared. Hispanic patients (mean age 41.5 ± 20.3 years vs 58.9 ± 19.9 years; p < 0.001) were significantly younger at onset compared with non-Hispanic patients, and AA patients were significantly younger at onset compared with White patients (mean age 38.6 ± 17.1 years vs 60.7 ± 19.4 years; p < 0.001). AA patients underwent thymectomy more frequently (63.6% vs 29.5%; p < 0.001) compared with White patients. After adjusting for covariates, AA patients were approximately 3 times more likely to experience hospitalization for MG crisis or exacerbation compared with White patients (odds ratio 2.77; 95% CI 1.19-6.50; p = 0.018).DiscussionDespite variations in disease severity and clinical profiles, long-term outcomes of patients did not differ. Our findings identify the areas of MG care that vary across racial and ethnic groups, which should be further addressed by clinicians.