Temporal trends in infective endocarditis: a population-based study in Olmsted County, Minnesota.

CONTEXT: Limited data exist regarding population-based epidemiologic changes in incidence of infective endocarditis (IE).

OBJECTIVE

To evaluate temporal trends in the incidence and clinical characteristics of IE.

DESIGN, SETTING, AND PATIENTS: Population-based survey using the resources of the Rochester Epidemiology Project of Olmsted County, Minnesota. One hundred seven IE episodes occurred in 102 Olmsted County residents between 1970 and 2000. The modified Duke criteria were used to validate the diagnosis of definite or possible IE.

MAIN OUTCOME MEASURES: Incidence of IE, proportion of patients with underlying heart disease, and causative microorganisms and clinical characteristics.

RESULTS

Age- and sex-adjusted incidence of IE ranged from 5.0 to 7.0 cases per 100,000 person-years during the study period and did not change significantly over time (P = .42 for trend). Infective endocarditis caused by viridans group streptococci was the most common organism-specific subgroup, with an annual adjusted incidence of 1.7 to 3.5 cases per 100,000; in comparison, IE due to Staphylococcus aureus had an annual adjusted incidence of 1.0 to 2.2 cases per 100,000. No time trend was detected for either pathogen group (P = .63 and P = .66, respectively). An increasing temporal trend was observed in the proportions of prosthetic valve IE cases (P = .09). Among people with underlying heart disease, there was an increasing temporal trend in mitral valve prolapse (P = .04) and a decreasing trend in rheumatic heart disease (P = .08). However, the absolute numbers were small. There was no time trend in rates of valve surgery or 6-month mortality during the study period (P = .97 and P = .59, respectively).

CONCLUSIONS

In this community-based temporal trend study, we found no substantial change in the incidence of IE over the past 3 decades. Viridans group streptococci continue to outnumber S aureus as the most common causative organisms of IE in this population.