Comparison Of Hospital Outcomes Between Covid 19 Myocarditis And Non-covid-19 Myocarditis

INTRODUCTION: Myocarditis commonly results from viral infections, which causes inflammation of the heart muscles. This could lead to adverse outcomes such as prolonged hospitalizations, cardiogenic shock, cardiac arrest, and event death. Studies have shown that COVID-19 could lead to myocarditis. However, the differences between COVID-19 myocarditis and non-COVID-19 myocarditis have not been explored. HYPOTHESIS: We hypothesized that adverse hospital outcomes such as in-hospital mortality, cardiogenic shock, cardiac arrest, mechanical ventilation, and acute respiratory distress syndrome would be higher among hospitalizations for COVID-19 myocarditis, compared to non-COVID-19 myocarditis. METHODS: We conducted a retrospective analysis of data collected in California State Inpatient Database (SID) during 2019 and 2020. We included data from all hospitalizations for COVID-19 myocarditis during 2020 and compared with data from all hospitalizations for non-COVID-19 myocarditis during 2019. ICD-10-CM diagnosis codes were used to identify procedures and conditions. Cox proportional and logistic regression analyses were done to compare the outcomes between the two groups. RESULTS: A total of 1,165 non-COVID-19 myocarditis and 575 COVID-19 myocarditis hospitalizations were included for the analysis. Nearly 45% of COVID-19 myocarditis hospitalizations were ≥65 years, while 52.3% of non-COVID-19 myocarditis hospitalizations were between 18-44 years of age. The rates of in-hospital mortality (4.2% versus 31.5%, P<0.001), cardiac arrest (2.0% versus 8.8%, P<0.001), mechanical ventilation (10.4% versus 41.2%, P<0.001), and acute respiratory distress syndrome (0.3% versus 17.5%, P<0.001) were significantly higher among COVID-19 myocarditis hospitalizations, compared to non-COVID-19 myocarditis hospitalizations. Kaplan Meier survival analysis showed that survival rates among COVID-19 myocarditis hospitalizations were significantly lower than non-COVID-19 myocarditis hospitalizations, compared to non-COVID-19 myocarditis hospitalizations (logrank P<0.001). Cox proportional regression analysis showed that in-hospital mortality (hazard ratio [HR], 2.15; CI: 1.41-3.28) was significantly higher among COVID-19 myocarditis hospitalizations. Logistic regression analysis showed that the odds of cardiac arrest (odds ratio [OR], 3.23; 95% CI: 1.75-5.94), mechanical ventilation (OR, 5.65 95% CI: 4.09-7.81), and acute respiratory distress syndrome (OR, 72.56; 95% CI: 21.52-244.68) were significantly higher among COVID-19 myocarditis hospitalizations. CONCLUSIONS: Our study using a large administrative database found that COVID-19 myocarditis compared to non-COVID 19 myocarditis affected older individuals and was associated with greater rates of in-hospital mortality and adverse hospital outcomes. These findings highlight the different nature of COVID related myocarditis compared to other forms of acute myocarditis.