Hospital Outcomes Among Covid-19 Hospitalizations With Myocarditis: Results From California State Inpatient Database

INTRODUCTION: Patients with COVID-19 can develop myocarditis due to respiratory hypoxemia, hyperinflammation, as well as direct injury due to binding of the virus to the angiotensin-converting enzyme 2 receptors in myocyte. In this study we examined the association between myocarditis among COVID-19 hospitalizations and adverse hospital outcomes. HYPOTHESIS: We hypothesized that adverse hospital outcomes such as in-hospital mortality, cardiac arrest, cardiogenic shock, mechanical ventilation, and acute respiratory distress syndrome would be higher among COVID-19 hospitalizations with myocarditis. METHODS: The current study was a retrospective analysis of data collected in California State Inpatient Database (SID) during 2020. All hospitalizations for COVID-19 were included for the analysis. ICD-10-CM diagnosis was used to identify COVID-19 (U07.1) and myocarditis hospitalizations and other procedures and conditions. Propensity score match analysis, survival analysis, and conditional logistic regression were done to compare adverse clinical outcomes between COVID-19 patients with and without myocarditis. RESULTS: A total of 164,368 COVID-19 hospitalizations were included for the analysis. Among them, 575 (0.4%) hospitalizations had myocarditis. Prior to propensity score matching, the rate of in-hospital mortality was significantly higher among COVID-19 hospitalizations with myocarditis (29.8% versus 14.0%, P<0.001). Even after propensity score matching, the rate of in-hospital mortality was significantly higher among the myocarditis group (30.0% versus 17.5%, P<0.001). Supporting this finding, survival analysis with log-rank test also showed that 30-day survival rates were significantly lower among those with myocarditis (39.5% versus 46.3%, P<0.001). Conditional logistic regression analysis showed that the odds of cardiac arrest (OR,1.90; 95% CI, 1.16-3.14), cardiogenic shock (OR,4.13; 95% CI, 2.14-7.99), mechanical ventilation (OR,3.30 (2.47-4.41), and acute respiratory distress syndrome (OR, 2.49; 95% CI, 1.70-3.66) were significantly higher among those with myocarditis. CONCLUSIONS: Our study using a large administrative database found that myocarditis was associated with greater rates of in-hospital mortality and adverse hospital outcomes among COVID-19 patients. Early suspicion is important for prompt diagnosis and timely management.