Trends in Acute Myocarditis Related Pediatric Hospitalizations in the United States, 2007-2016.

There has been little exploration of acute myocarditis trends in children despite notable advancements in care over the past decade.  We explored trends in pediatric hospitalizations for acute myocarditis from 2007-2016 in the United States (US). This was a retrospective, serial cross-sectional study of the National Inpatient Sample database from 2007 to 2016, identifying patients ≤18 years hospitalized with acute myocarditis. Patient demographics and incidence trends were examined. Other relevant clinical and resource utilization outcomes were also explored. Out of 60,390,000 weighted pediatric hospitalizations, 6371 were related to myocarditis. The incidence of myocarditis increased from 0.7 to 0.9 per 100,000 children (p<0.0001) over the study period. The mortality decreased from 7.5% to 6.1% (p=0.02). A significant inflation-adjusted increase by $4,574 in the median hospitalization cost was noted (p=0.02) while length of stay (LOS) remained stable (median 6.1 days). Tachyarrhythmias were identified as the most common type of associated arrhythmia. The occurrence of congestive heart failure (CHF) remained steady at 27%. In conclusion, in-hospital mortality associated with pediatric acute myocarditis has decreased in the United States over years 2007-2016 with a concurrent rise in incidence. Despite steady length of stay, hospitalization costs have increased. Future studies investigating long-term outcomes relating to acute myocarditis are warranted.