Supplementary Material for: Acute Pericarditis-Associated Hospitalization in the USA: A Nationwide Analysis, 2003-2012

Background and Objectives: Epidemiologic data on hospitalizations for acute pericarditis are scarce. We sought to study the trends in these hospitalizations and outcomes in the USA over a 10-year period. Methods: We used the 2003-2012 Nationwide Inpatient Sample database to identify admissions with a primary diagnosis of acute pericarditis. Outcomes included hospitalization rate, case fatality rate (CFR), length of stay (LOS), hospital charges, complications and diagnostic and therapeutic procedures. Results: We observed an estimated 135,710 hospitalizations for acute pericarditis among patients ≥16 years during the study period (mean age 53.5 ± 18.5 years; 40.5% women). The incidence of acute pericarditis hospitalizations was significantly higher for men than for women [incidence rate ratio (IRR) 1.56; 95% confidence interval (CI) 1.54-1.58; p < 0.001]; it decreased from 66 to 54 per million person-years (p < 0.001). CFR and LOS declined significantly during the study period (CFR: 2.2% in 2003 to 1.4% in 2012; LOS: 4.8 days in 2003 to 4.1 days in 2012; p < 0.001 for both). The average inflation-adjusted health-care charge increased from USD 31,242 to 38,947 (p < 0.001). Conclusion: The hospitalization rate, CFR and LOS associated with acute pericarditis have declined significantly in the US population. Average charges for acute pericarditis hospitalization have increased.