Epidemiology of bacterial endocarditis in The Netherlands. II. Antecedent procedures and use of prophylaxis.

BACKGROUND: The reported frequency with which endocarditis is ascribed to an antecedent dental or medical procedure varies from 3% to 62%.

METHODS: We performed a nationwide prospective study of the epidemiology of bacterial endocarditis in the Netherlands. During a 2-year period, all consecutively hospitalized patients suspected of having endocarditis were visited while still hospitalized for a review of the medical record and an in-person interview that focused on antecedent procedures and administered prophylaxis. All information was checked with pharmacists and dental and medical practitioners.

RESULTS: Of 427 patients with late prosthetic or native valve endocarditis, 275 were eligible for antibiotic prophylaxis because of a previously known cardiac lesion (n = 197) or a prosthetic valve (n = 78). Of these 275 patients, 64 (23.3%) had undergone a procedure with an indication for prophylaxis within 180 days of onset; in 31 (11.3%) the procedures had been within 30 days of onset. Antibiotic prophylaxis had been administered to 17 (26.6%) of the 64 patients and to eight (25.8%) of the 31 patients.

CONCLUSION: The results indicate that medical and dental procedures cause only a small fraction of endocarditis. The majority of patients develop the disease along other routes. For an incubation period of 180 days, full compliance with prophylaxis might have prevented endocarditis in 47 (17.1%) of 275 patients with late prosthetic or native valve endocarditis involving a previously known cardiac lesion who underwent a procedure with an indication for prophylaxis. For an incubation period of 30 days, prophylaxis might have prevented endocarditis in 23 (8.4%) of these 275 patients, or 5.3% of all patients with endocarditis (n = 427).