Objective  To analyze the changing trends of the disease burden caused by myocarditis from 1990 to 2021 and predict its future trend from 2022 to 2040 in China, and provide data support and reference for the prevention and treatment of myocarditis in China.

Methods Joinpoint regression model was used to calculate the average annual percentage change (AAPC) of in disease burden by myocarditis in China, in the world, and in regions with different socio-demographic indices (SDIs) to analyze overall trends. Annual percentage changes (APC) were calculated to assess the annual variations in China from 1990 to 2021. Predictive analysis on the disease burden in China from 2022 to 2040 was conducted by using auto-regressive integrated moving average (ARIMA) model in software R.

Results In terms of the prevalence, incidence, death, and disability-adjusted life years (DALYs) of myocarditis, there was an overall increase in 2021 compared with 1990. Regarding age-standardized rates, all the rates showed declines except for the prevalence, which increased compared with 1990. From 1990 to 2021, the age-standardized prevalence rate, age-standardized incidence rate, age-standardized mortality rate, and age-standardized DALYs rate of myocarditis all showed significant changes in China (AAPC=0.70%, −0.21%, −0.69%, −1.79%, all P<0.05). Gender-specific analysis showed that age-standardized prevalence, incidence, mortality, and DALYs rates were higher in men than in women in 2021. Age-group analysis revealed the peaks in prevalence, DALYs, age-standardized prevalence rate, and DALYs rate in children under 5 years and elderly individuals aged 65–<75 years. Predictions for 2022–2040 indicated that the age-standardized prevalence rate would remain stable (higher than 2021 level in some years) and might increase, while the age-standardized incidence, mortality, and DALYs rates would decline, slightly lower than 2021 levels in China.

Conclusion Between 1990 and 2021, the age-standardized prevalence rate of myocarditis showed an upward trend, while the age-standardized incidence rate, age-standardized mortality rate, and age-standardized DALYs rate all exhibited downward trends in China. Notably, in 2021, the age-standardized prevalence rate, incidence rate, mortality rate, and DALYs rate of myocarditis were all higher than the global average. Furthermore, key groups such as men, children, and the elderly exhibited higher age-standardized prevalence rate and DALYs rate of myocarditis. The prediction indicated that the prevalence rate of myocarditis would increase in the future, suggesting that China still faces significant challenges in the prevention and management of myocarditis. It is necessary to strengthen disease surveillance in key populations, improve diagnostic and treatment of myocarditis to reduce its impact on the people’s health in China.