One-Year Risk of Myocarditis After COVID-19 Infection: A Systematic Review and Meta-analysis

BACKGROUND: Acute myocarditis has been described as a relatively rare cardiovascular complication of COVID-19 infection. However, data regarding the risk of myocarditis during the post-acute phase of COVID-19 are scant. We assess the risk of incident myocarditis in COVID-19 survivors within 1 year from the index infection by a systematic review and meta-analysis of the available data. METHODS: Data were obtained by searching Medline and Scopus for all studies published at any time up to September 1, 2022, and reporting the long-term risk of incident myocarditis in COVID-19 survivors. Myocarditis risk data were pooled using the Mantel-Haenszel random-effects models with hazard ratio (HR) as the effect measure with 95% confidence interval (CI). Heterogeneity among studies was assessed using the Higgins-Thompson I(2) statistic. RESULTS: Overall, 20,875,843 patients (mean age 56.1 years, 59.1% male) were included in this analysis. Of them, 1,245,167 experienced (and survived) COVID-19 infection. Over a mean follow-up of 9.5 months, myocarditis occurred to 0.21 (95% CI 0.13-0.42) out of 1000 patients survived to COVID-19 infection compared with 0.09 [95% CI 0.07-0.12) out of 1000 control subjects. Pooled analysis revealed that recovered COVID-19 patients presented an increased risk of incident myocarditis (HR 5.16, 95% CI 3.87-6.89; P < 0.0001; I(2) = 7.9%) within 1 year from the index infection. The sensitivity analysis confirmed yielded results. CONCLUSIONS: Our findings suggest that myocarditis represents a relatively rare but important post-acute COVID-19 sequelae.