INCIDENCE OF INFECTIVE ENDOCARDITIS IN THE DELAWARE VALLEY, 1988-1990

This population-based study aimed to determine the incidence of native , prosthetic, and bioprosthetic valve nosocomial infective endocarditi s (IE), and IE associated with the use of injected drugs. Patients wit h IE during 27 months over the years 1988 to 1990, and residing in any of 6 counties in the Philadelphia metropolitan area were identified. An expert panel reviewed all patients to verify the diagnosis. Inciden ce rates were estimated after adjustment for failure to recruit and un derreporting. Of 853 potential patients, 670 (79%) met the inclusion c riteria. The overall incidence rate of IE was 11.6 cases/100,000 perso n-years (95% confidence interval [CI] 10.8 to 12.4). The rates for spe cific types of IE were: 4.45 (95% CI 3.97 to 4.94) for community-acqui red native valve, 0.94 (95% CI 0.72 to 1.12) for prosthetic valve, 0.9 4 (95% CI 0.71 to 1.16) for nosocomial, and 5.34 (95% CI 4.80 to 5.87) for IE associated with use of injected drugs. Previous population stu dies found overall incidence rates of 1.7 to 4 cases/100,000 person-ye ars, similar to our rate for community-acquired native valve IE. Type- specific rates have not been-previously reported. The higher overall r ate in this study is partly related to the high prevalence of injectio n drug use in our area.