Trends in the use of echocardiography in patients with Staphylococcus aureus bacteremia: an analysis using the Nationwide Inpatient Sample data

Background: Infective endocarditis occurs in approximately 10%-30% of patients with Staphylococcus aureus bacteremia (SaB). Guidelines recommend echocardiography in patients with SaB and risk factors for infective endocarditis in the absence of any obvious source of infection. Herein, we explored the trends in the use of echocardiography in patients with SaB and its relationship to outcomes using a large national database. Method: All patients with a principal discharge diagnosis of SaB were identified using the National Inpatient Sample database from 2001 to 2014. Procedure code 88.72 was used to identify echocardiography. Logistic regression models were estimated to identify the year-over-year trends in echocardiogram, predictors of use, and association with mortality. Results: From 2001 to 2014, there were 668 423 hospitalizations with SaB diagnosis and 86 387 (12.9%) had echocardiogram. The rate of echocardiography increased from 10.7% in 2001 to 15.2% in 2014 (p_trend < 0.001). Major predictors of echocardiogram usage were younger age, male gender, presence of sepsis, valvular or congenital heart disease, prosthetic heart valve (PHV), cardiac implantable electronic device (CIED), hemodialysis, and drug abuse. The adjusted rates of echocardiography increased from approximately 10% to 15% in hospitalizations without risk factors for IE while for high-risk groups like PHV and CIED it remained constant at 30% and 19%, respectively. Echocardiography was associated with 31% lower odds of in-hospital mortality. Conclusion: The increase in echocardiography rate was largely attributable to increased use in those without risk factors while usage in those with PHV and CIED remained much lower than expected. Echocardiography use was associated with lower risk-adjusted mortality. These findings require further study and confirmation.