Mortality of myasthenia gravis: a national population-based study in China

Objective: As a potentially life-threatening condition, myasthenia gravis (MG) has limited epidemiological studies on mortality. We aim to provide demographic distribution, geographical variation, and temporal trend of MG-related mortality in China. Methods: The national population-based analysis was conducted based on records derived from the National Mortality Surveillance System of China. All deaths related to MG were identified from 2013 to 2020, and MG-related mortality was evaluated by sex, age, location, and year. Results: A total of 4224 deaths were related to MG during 2013-2020, and the median age at death of MG was 59.45 years, significantly lower than that in the general population (75.47 years, P < 0.05). In 2020, the age-standardized mortality rate of MG was 1.86 per million people and markedly higher in males than in females (2.37 vs. 1.31 per million). The mortality rate per million was lower than 1 in young children, peaking at 2.83 only in males (vs. 0.36 in females) aged 10-19 years, and substantially increased with age, reaching the highest rate of 13.31 for males and 10.58 for females aged 80 years and older. Geographical disparity across China was observed with the highest age-standardized mortality rate in Southwest (2.53 per million). From 2013 to 2020, MG-related mortality rate showed an increasing trend with the average annual percentage change of 3.5% (95% CI, 1.4-5.6). The notable increases occurred in age 10-19 years and over 70 years. Interpretation: In China, MG-related mortality was notably high among adolescent males and the elderly. The increasing death burden due to MG highlight challenges to disease management.