DENTAL AND CARDIAC RISK-FACTORS FOR INFECTIVE ENDOCARDITIS - A POPULATION-BASED, CASE-CONTROL STUDY

Background: Although antibiotic prophylaxis against infective endocard itis is recommended, the true risk factors for infective endocarditis are unclear. Objective: To quantitate the risk for endocarditis from d ental treatment and cardiac abnormalities. Design: Population-based, c ase-control study Setting: 54 hospitals in the Philadelphia area. Pati ents: Persons with community-acquired infective endocarditis not assoc iated with intravenous drug use were compared with community residents , matched by age, sex, and neighborhood of residence. Measurements: In formation on demographic characteristics, host risk factors, and denta l treatment was obtained from structured telephone interviews, dental records, and medical records. Results: During the preceding 3 months, dental treatment was no more frequent among case-patients than control s (adjusted odds ratio, 0.8 [95% CI, 0.4 to 1.5]). Of 273 case-patient s, 104 (38%) knew of previous cardiac lesions compared with 17 control s (6%) (adjusted odds ratio, 16.7 [Cl, 7.4 to 37.4]). Case-patients mo re often had a history of mitral valve prolapse (adjusted odds ratio, 19.4 [Cl, 6.4 to 58.4]), congenital heart disease (adjusted odds ratio , 6.7 [Cl, 2.3 to 19.4]), cardiac valvular surgery (adjust ed odds rat io 74.6 [CI, 12.5 to 447]), rheumatic fever (adjusted odds ratio, 13.4 [CI, 4.5 to 39.5]), and heart murmur without other known cardiac abno rmalities (adjusted odds ratio, 4.2 [CI, 2.0 to 8.9]). Among case-pati ents with known cardiac lesions-the target of prophylaxis - dental the rapy was significantly (P = 0.03) less common than among controls (adj usted odds ratio, 0.2 [Cl, 0.04 to 0.7] over 3 months). Few participan ts received prophylactic antibiotics. Conclusions: Dental treatment do es not seem to be a risk factor for infective endocarditis, even in pa tients with valvular abnormalities, but cardiac valvular abnormalities are strong risk factors. Few cases of infective endocarditis would be preventable with antibiotic prophylaxis, even with 100% effectiveness assumed. Current policies for prophylaxis should be reconsidered.