Contemporary Postnatal Incidence of Acquiring Acute Myocarditis by Age 15 Years and the Outcomes From a Nationwide Birth Cohort.

OBJECTIVES

Acute myocarditis can be lethal, but the incidence remains unclear because of its wide manifestation spectrum. We investigated the postnatal incidence of acute myocarditis and risk factors for morbidity and mortality.

DESIGN

Retrospective derived birth cohort study.

SETTING

Taiwan National Health Insurance Database for the period 2000-2014.

PATIENTS

Children born between 2000 and 2009 with complete postnatal medical care data for at least 5 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From among 2,150,590 live births, we identified 965 patients (54.8% male) admitted with the diagnosis of acute myocarditis, accounting for an overall incidence of 0.45/1,000. The cumulative incidence rates were 0.19/1,000, 0.38/1,000, 0.42/1,000, and 0.48/1,000 by ages 1, 5, 10, and 15 years, respectively. Male predominance was noted in infants and school age children (age group 6-14 yr). Arrhythmias, including tachyarrhythmia (4.8%) and bradyarrhythmia (1.1%), occurred in 56 patients. Extracorporeal membrane oxygenation support was provided to 62 patients (6.4%) and additional left ventricular assist devices in six of them. The mortality at discharge was 6.3%. The presence of ventricular tachyarrhythmia, bradyarrhythmia, and an onset at school age (6-14 yr) were associated with increased odds for the need for extracorporeal membrane oxygenation, which was the only predictor for mortality at discharge (hazard ratio, 7.85; 95% CI, 3.74-9.29). In patients who survived the acute myocarditis, late mortality was relatively low (36/904 = 4.0%). The overall survival of children with acute myocarditis were 90.9%, 90.3%, and 89.8% by the intervals of 1, 5, and 10 years after the myocarditis, respectively.

CONCLUSIONS

This birth cohort study determined the cumulative incidence of acute myocarditis for neonates by 15 years old to be one in 2,105. In an era of extracorporeal membrane oxygenation, the need of extracorporeal membrane oxygenation may reflect the severity of acute myocarditis and predict its outcome.