From 1998 through 2013, the standardized incidence of infective endocarditis in New York and California remained stable between 7.6 and 7.8 cases per 100,000 persons each year, according to a retrospective database analysis. During that same period, the adjusted mortality risk related to infective endocarditis decreased 2 percent per year.

Lead researcher Nana Toyoda, MD, of the Icahn School of Medicine at Mount Sinai Medical Center in New York, and colleagues published their results online April 25 in JAMA.

The researchers noted that U.S. guidelines used to recommend antibiotic prophylaxis for patients with structural valve disease undergoing invasive procedures. However, in 2007, new recommendations from the American Heart Association suggested using prophylaxis only for patients undergoing specific dental procedures and with a history of valve replacement or repair, prior infective endocarditis, uncorrected congenital cyanotic heart lesions or cardiac transplantation with valvulopathy.

For this study, the researchers identified 75,829 adults from the Statewide Planning and Research Cooperative System database in New York and the Office of Statewide Health Planning and Development database in California. All of the patients had a first episode of endocarditis between 1998 and 2013.

The researchers categorized infective endocarditis as native-valve endocarditis, prosthetic-valve endocarditis, cardiac device–related endocarditis or drug abuse–related endocarditis.

The mean age was 62.3 years old, and 59.1 percent of patients were males. Of the patients, 56.9 percent were from California and 43.1 percent were from New York.

During the study, the crude incidence of endocarditis increased from 7.6 to 9.3 cases per 100,000 persons annually. However, after adjusting for age, sex and race, the incidence did not significantly change over time.

From 1998 through 2013, the proportion of patients with a history of valve surgery increased from 12.8 percent to 15.2 percent, while the proportion of patients with implanted pacemakers or defibrillators increased from 8.8 percent to 15.6 percent. Both of those increases were statistically significant.

Meanwhile, the proportion of patients with native-valve endocarditis significantly decreased from 74.5 percent to 68.4 percent, the proportion of patients with prosthetic-valve endocarditis significantly increased from 12 percent to 13.8 percent and the proportion of patients with cardiac device–related endocarditis significantly increased from 1.3 percent to 4.1 percent.

The crude 90-day mortality rates were 23.9 percent in 1998 and 24.2 percent in 2011, which was not significantly different. However, when the researchers adjusted for patient demographics and comorbidities, the mortality risk significantly decreased 2 percent per year.

The mortality rates were 37.1 percent at 1 year and 52.9 percent at 5 years. In addition, the proportion of patients who underwent cardiac surgery during or within 30 days of their index admission increased during the study from 10.6 percent to 13.3 percent.

The researchers mentioned a few limitations of the study, including that the data sets could be subject to inaccurate coding and could lead to unmeasured confounders. They also did not have information on whether patients underwent skilled nursing care or wound care. In addition, they did not know when the blood cultures were performed during hospitalization and could not account for patients who recently moved from different states or countries. Further, they noted that the most recent data were four years old, so the findings might not reflect current characteristics and outcomes associated with infective endocarditis.