Incidence and complication rate of infective endocarditis in the Dutch region of Walcheren: a 3-year retrospective study

Objective - To measure the incidence of infective endocarditis (IE) in the region of Walcheren and to estimate the complication and comorbidity rate of IE, we conducted a 3-year retrospective study of IE in the only hospital (Ziekenhuis Walcheren) of the region between January, 2002 and December, 2004. Results - The total number of cases was 32. The calculated yearly incidence of IE was 9.61 cases per 100.000 inhabitants per year. The median age was 64 years (range 36-81 years). When applying the Duke criteria 28 patients (87.5%) were classified as definite IE and 4 patients (12.5%) as possible IE. Blood cultures were positive in 27 patients (84.4%). The most commonly isolated organisms were streptococci (37.5%). Staphylococcus aureus was isolated in 31.3% of positive blood cultures. Enteroccocus faecalis was identified in 3 cases (9.4%). In only 15.6% of the cases was the course of IE uncomplicated. The most frequent complications were heart failure (59.4%) and embolic events (34.4%). Cardiac surgery was performed in 37.5% of the cases. Concomitant morbidity was found in 75% of the patients. Especially, the high incidences of diabetes mellitus (28.1 %), chronic renal failure (28.1 %) and chronic obstructive pulmonary disease (21.9%) were remarkable. Conclusion - The calculated incidence of IE of 9.61 cases per 100,000 inhabitants per year was more than five times higher than the one reported in a nation-wide Dutch study of 1992. The present study demonstrates that IE remains a disease with a considerable mortality and complication rate. The majority of the patients with I E had non-cardiac comorbidity. Especially, the prevalence of diabetes mellitus and chronic renal failure in our population of patients with IE is remarkable.