In accordance with the 2007 American College of Cardiology and American Heart Association infective endocarditis (IE) guideline update, antibiotic prophylaxis is now being restricted to a smaller number of cardiac conditions with very high risk for adverse outcomes from IE. However, there is scant data on IE trends since this major practice change in the United States.

The aim of this study was to compare temporal trends in IE incidence, microbiology, and outcomes before and after the change in the 2007 IE prophylaxis guideline in the United States.

The NIS (Nationwide Inpatient Sample) database was used to investigate IE hospitalization rates in the United States from 2000 through 2011. The mean annual rates of IE before and after the 2007 guideline change were compared using segmented regression analysis.

There were 457,052 IE-related hospitalizations in the United States from 2000 to 2011, with a steady increase in incidence (p < 0.001). The trend in IE hospitalization rates from 2000 to 2007 and from 2008 to 2011 was not significantly different (p = 0.74). The increases in the number of Staphylococcus IE cases per million population during the study periods 2000 to 2007 and 2008 to 2011 were similar (p = 0.13), but Streptococcus IE hospitalization rates were significantly higher after the release of new guidelines (p = 0.002). Finally, valve replacement rates for IE steadily increased from 2000 to 2007 (p = 0.03) but showed a plateau from 2007 to 2011. Overall, there was no significant difference in the rates of valve replacement for IE before and after the release of new guideline (p = 0.23).

These results show that IE incidence has increased in the United States over the past decade. With regard to the microbiology of IE, there has been a significant rise in the incidence of Streptococcus IE since the 2007 guideline revisions. However, the rates of hospitalization and valve surgery for IE have not increased since the change in IE prophylaxis guideline in 2007.