Incidence and risk factors of myocarditis in hospitalized patients with COVID-19 in Germany

Abstract Background In December 2019 first patient cases of pneumonia caused by a previously unknown virus was detected in China. This began the coronavirus disease 2019 (COVID-19)-pandemic with a never seen infectious disease burden and impact on the healthcare systems worldwide. The first severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections in Germany were reported on January 27th, 2020. From this initial cluster (in Bavaria), a sustained transmission of SARS-CoV-2 was followed by a substantial spread of COVID-19 in the German population. Although COVID-19 is frequently accompanied by symptoms like fever, cough, sore throat, malaise, myalgias, and dyspnoea, and the infection affects the lungs primarily, COVID-19 might also lead to acute cardiac, kidney, and liver injury. Cardiac complications, particularly myocarditis, and pericarditis, were associated with SARS-CoV-2 infection. Viral infections are frequent causes of myocarditis, an inflammation of the myocardium, which may result in hospitalization and heart failure and can be followed by sudden cardiac death. Myocarditis as cardiac involvement in COVID-19 infection is well known. Real-world data about incidence in hospitalized COVID-19 patients and risk factors for myocarditis in COVID-19 patients are sparse. Methods We used the German nationwide inpatient sample to analyze all hospitalized patients with confirmed COVID-19-diagnosis in Germany in 2020 and stratified them for myocarditis (source: RDC of the Federal Statistical Office and the Statistical Offices of the federal states, DRG Statistics 2020, own calculations). Results Overall, 176,137 hospitalizations (52.3%males, 53.6%aged≥70years) with confirmed COVID-19-infection were coded in Germany in 2020, and among them, 226 (0.01%) had myocarditis (incidence:1.28 per 1000 hospitalization cases). Absolute numbers of myocarditis increased, while relative numbers decreased with age. COVID-19 patients with myocarditis were younger (64.0 [IQR 43.0/78.0] vs.71.0 [56.0/82.0], P