Abstract
OBJECTIVES: This study aimed to analyse the burden of myocarditis in the Western Pacific Region (WPR). DESIGN AND SETTING: Data from the Global Burden of Disease (GBD) Study 2021, covering 31 countries in the WPR, were analysed. PARTICIPANTS: Patients diagnosed with myocarditis. OUTCOME MEASURES: Numbers and age-standardised rates (ASRs) of incidence, prevalence, mortality and disability-adjusted life years (DALYs), along with their average annual percentage changes (AAPCs), were included. The contributions of population growth, ageing and epidemiological changes to ASR changes were assessed. Additionally, the ASRs of four indicators are projected until 2035. RESULTS: In 2021, GBD estimates for myocarditis were 375 241.19 incident cases, 15 307.52 deaths and 379 674.28 DALYs in the WPR. From 1990 to 2021, the incidence, prevalence and mortality increased by 53.58%, 67.88% and 67.16%, respectively, whereas DALYs decreased by 24.77%. ASRs declined across all metrics: incidence (17.68 to 16.70 per 100,000; AAPC = -0.18, 95% CI -0.19 to -0.18), mortality (0.82 to 0.64 per 100,000; AAPC = -0.78, 95% CI -0.83 to -0.72) and DALYs (35.69 to 19.36 per 100,000; AAPC = -1.97, 95% CI -2.02 to -1.89). Papua New Guinea exhibited the highest increases in incidence, prevalence, deaths and DALYs. Japan, Singapore, China and Kiribati had the highest age-standardised incidence rate (ASIR), prevalence rate (ASPR), mortality rate (ASMR) and DALY rate (ASDR), respectively. Individuals aged ≥65 years and infants had significantly higher ASIR, ASMR and ASDR. Males consistently demonstrated higher myocarditis ASRs than females in the WPR from 1990 to 2021. Ageing was identified as the primary driver of increased incidence and mortality. Projections indicate that the ASIR of myocarditis will remain stable through 2035. CONCLUSION: The burden of myocarditis in the WPR exhibits substantial cross-country variation, with males, infants and the elderly disproportionately affected, underscoring the urgent need for context-specific management strategies tailored to high-risk populations and regional epidemiological profiles.