Expert Review: Valve Disease

Temporal Trends in infective endocarditis in the context of prophylaxis guideline modifications

The present study evaluats the impact of the restriction of antibiotic prophylaxis on the incidence of infective endocarditis (IE), based on recent guidelines. The authors found that changes in IE antibiotic prophylaxis guidelines have not given rise to an increase in oral streptococci IE, which supports a posteriori the reduction of its use. However, an increase of staphylococcal IE in a population of patients not identified as ‘at risk’ for IE was observed.

Background 

In 2007 and 2009 infective endocarditis (IE) prophylaxis guidelines were altered toward a drastic reduction in antibiotic indications (in France this occurred as early as 2002). This change led to restricting the use of antibiotic prophylaxis in patients with the highest risk of poor outcomes from IE (i.e., patients with prosthetic valves, complex congenital heart disease, previous IE).

Knowledge Gap

The evaluation of the impact of this drastic change in IE prophylaxis strategy on clinical and epidemiological characteristics of incident IE has not been evaluated.

Aim of the Study

The objective was to evaluate temporal trends in IE incidence, clinical characteristics, and prognosis following the 2002 French IE prophylaxis guideline modifications.

Methods

The present study was designed as a population-based survey study. Three one-year surveys were conducted for the years 1991, 1999 and 2008 including 11,000,000 inhabitants from three French regions. Only patients ≥20 years of age with a first hospitalization between January 1st and December 31st of each year and residing in these three regions were kept in the analysis. Expert validated IE cases were reported.

Results

Overall, 993 expert-validated IE cases were analyzed (323 in 1991; 331 in 1999; and 339 in 2008). IE incidence remained stable over time (95% confidence intervals given in parentheses/brackets): 35 (31 to 39), 33 (30 to 37), and 32 (28 to 35) cases per million in 1991, 1999, and 2008, respectively. Oral streptococci IE incidence did not increase in the whole patient population (8.1 [6.4 to 10.1], 6.3 [4.8 to 8.1], and 6.3 [4.9 to 8.0] in 1991, 1999, and 2008, respectively), nor in patients with pre-existing native valve disease. The increased incidence of Staphylococcus aureus IE (5.2 [3.9 to 6.8], 6.8 [5.3 to 8.6], and 8.2 [6.6 to 10.2]) was not significant in the whole patient population (p = 0.228) but was significant in the subgroup of patients without previously known native valve disease (1.6 [0.9 to 2.7], 3.7 [2.6 to 5.1], and 4.1 [3.0 to 5.6]; p = 0.012).

Conclusion

Despite marked modifications of IE prophylaxis recommendations between 1999 and 2008 toward a reduction of antibiotic use, the present  study did not identify any increase either in the overall incidence rate of IE or in that of oral streptococcal IE incidence rate. However, an increase of staphylococcal IE was observed in a population of patients not identified as at risk for IE.

Perspective-Clinical Impact 

To date, changes in IE antibiotic prophylaxis guidelines have not given rise to an increase in oral streptococci IE, which supports a posteriori the reduction of its use. This fact should prompt a decrease in the unnecessary consumption of antibiotics, a source of ever-increasing bacterial resistance.

The increased incidence of staphylococci must be considered in the light of the increased number of patients with prosthetic valve IE, pacemaker IE, diabetes mellitus, and all conditions associated with staphylococcal bacteremia. Therefore, S. aureus bacteremia prevention is necessary not only in patients with previously known valve diseases but also in patients without such disease.

However, study findings should be interpreted in the light of certain limitations. Under-reporting of incident cases, the possibility of treating incident IE cases outside the surveyed regions, and the use of different IE classification criteria at the time of each survey have been acknowledged by the authors. Furthermore, the present study did not report practitioner compliance with these new recommendations, and the low incidence of the disease would allow detection of only a major increase in incidence. Finally, the comparison of IE incidence between the 1991 and 2008 time intervals may be biased by an improvement in IE diagnosis performance due to medical progress (i.e., an improvement in echocardiographic or microbiological techniques increasing their sensitivity and the diagnosis of IE).

Corresponding author from original paper

Dr. Xavier Duval, Centre d’Investigation Clinique, Hôpital Bichat Claude Bernard, Université Paris VII, 46 rue Henri Huchard, 75877 Paris Cedex 18, France. E-mail: xavier.duval@bch.aphp.fr.

Citation: J Am Coll Cardiol, 2012; 59:1968-1976

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