Demographic and Geographic Trends in Myasthenia Gravis–Related Mortality in the United States, 1999–2022

The prevalence and incidence of myasthenia gravis (MG) have been increasing, globally and in the United States. The literature lacks data on MG-related mortality (MGRM) and its trends in the United States. We aimed to examine nationwide demographic and geographic trends of MGRM from 1999 to 2022. This retrospective population-based study used data regarding MG-related deaths (MGRD) from Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research mortality records. The International Classification of Diseases (ICD) code, G70.0, was used to identify MG. We stratified deaths by sex, age groups (25-64 years and older than 64 years), race and ethnicity, and geographical location. Joinpoint regression was performed to examine trends in age-adjusted mortality rates (AAMRs). Sensitivity analysis was performed using MG as an underlying cause of death (UCD). During the study period, there were 37,075 MGRD (89.6% were older than 64 years, and 44.7% were female individuals). From 1999 to 2022, the MG-related AAMR increased significantly from 6.21 (95% CI 5.58-6.58) per 1 million population to 9.51 (95% CI 9.14-9.88) per 1 million population, with an average annual percent change of +2.42 (95% CI 1.98-2.87). The increase in MGRM was observed regardless of age group, sex, region, or race and ethnicity. The MG-related AAMR increased by 66.3% in male individuals and 29.6% in female individuals over the study period. For individuals aged 65 years or older, there was a concerning increase in MG-related AAMR by 82.35% from 28.23 to 47.36. There was a peak in MGRM during the coronavirus disease 2019 pandemic (2020-2022), and sensitivity analysis revealed that the trend in MGRM remained consistent as both UCD and contributing cause of death. The rising MGRM over the 23-year period is concerning and warrants investigation into the underlying causes for this trend. This increase was most prominent in older and male individuals. The growing burden of MG in the United States and globally might pose a serious challenge to health care in the future. Limitations of this study include reliance on ICD codes. Future work needs to take these trends and disparities into consideration and focus on improving MGRM.