Long-term outcome of infective endocarditis: a study on patients surviving over one year after the initial episode treated in a Finnish teaching hospital during 25 years

Abstract

Background: Only a few previous studies have focused on the long-term prognosis of the patients with infective endocarditis (IE). Our purpose was to delineate factors potentially associated with the long-term outcome of IE, recurrences of IE and requirement for late valve surgery.

Methods: A total of 326 episodes of IE in 303 patients were treated during 1980-2004 in the Turku University Hospital. We evaluated the long-term outcome and requirement for late valve surgery for 243 of these episodes in 226 patients who survived longer than 1 year after the initial admission. Factors associated with recurrences were analysed both for the 1-year survivors and for all 303 patients.

Results: The mean (SD) follow-up time for the 1-year survivors was 11.5 (7.3) years (range 25 days to 25.5 years). The overall survival was 95%, 82%, 66%, 51% and 45% at 2, 5, 10, 15 and 20 years. In age and sex adjusted multivariate analyses, significant predictors for long-term overall mortality were heart failure within 3 months of admission (HR 1.97, 95% CI 1.27 to 3.06; p = 0.003) and collagen disease (HR 2.54, 95% CI 1.25 to 5.19; p = 0.010) or alcohol abuse (HR 2.39, 95% CI 1.30 to 4.40; p = 0.005) as underlying conditions, while early surgery was significantly associated with lower overall mortality rates (HR 0.31, 95% CI 0.17 to 0.58; p < 0.001). Heart failure was also significantly associated with the long-term cardiac mortality (p = 0.032). Of all 303 patients, 20 had more than 1 disease episode. Chronic dialysis (p = 0.002), intravenous drug use (p = 0.002) and diabetes (p = 0.015) were significant risk factors for recurrent episodes of IE, but when analysed separately for the 1-year survivors, only chronic dialysis remained significant (p = 0.017). Recurrences and late valve surgery did not confer a poor prognosis.

Conclusion: Heart failure during the index episode of IE was the complication, which significantly predicted a poor long-term outcome. Patients who underwent surgery during the initial hospitalisation for IE faired significantly better than those who did not.

Figures

Figure 1

Kaplan-Meier curves of the overall mortality and cardiac mortality for 243 episodes of infective endocarditis in 226 patients, who survived longer than 1 year after the initial episode. The numbers at different time points refer to the number of patients being followed up and at risk for event at the beginning of the time period. Zero on the time access indicates 1 year.

Figure 2

Long-term outcome was analysed for 243 episodes of infective endocarditis in 226 patients, who survived longer than 1 year after the initial episode. Kaplan-Meier curves of the overall survival for patients with and without heart failure during 3 months of admission (a), and for those undergoing and not undergoing early (in-hospital) surgery (b). The numbers at different time points refer to the number of patients being followed up and at risk for event at the beginning of the following time period. Zero on the time access indicates 1 year.

Figure 3

Kaplan-Meier curves of survival free of recurrent endocarditis, valve replacement, and death after an episode of infective endocarditis. The numbers at different time points refer to the number of patients being followed up and at risk for event at the beginning of the following time period. Zero on the time access indicates 1 year.