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Infective endocarditis. Olmsted County, Minnesota, 1950 through 1981
Abstract:
Strict criteria were used to identify all definite, probable, and possible cases of endocarditis in residents of Olmsted County, Minnesota, from 1950 through 1981. The mean annual age- and sex-adjusted incidence rates per 100,000 person-years were 3.8 for total cases and 3.2 for definite and probable cases only. Total rates were 4.3 for 1950 through 1959, 3.3 for 1960 through 1969, and 3.9 for 1970 through 1981. Rheumatic heart disease was the underlying disorder in 26% of cases, with a shift noted during 1970 through 1981 to involvement of prosthetic rather than natural valves in these patients. Mitral valve prolapse was identified in 17% of cases. No source of infection could be identified in 41% of cases, including half of those cases with rheumatic or congenital heart disease. In cases diagnosed prior to autopsy, the 60-day fatality fell from 46% during 1950 through 1959 to 22% and 26% during 1960 through 1969 and 1970 through 1981, respectively.
Insights
Endocarditis incidence remained stable in Olmsted County, Minnesota, from 1950-1981. However, fatality rates for diagnosed endocarditis cases significantly decreased over this period.
Area of Science:
- Epidemiology
- Cardiovascular Medicine
- Infectious Diseases
Background:
- Endocarditis is a serious infection affecting the heart valves.
- Understanding long-term incidence and outcomes is crucial for public health.
- Olmsted County, Minnesota, has a robust medical records linkage system for epidemiological studies.
Purpose of the Study:
- To determine the incidence of endocarditis in Olmsted County, Minnesota, between 1950 and 1981.
- To analyze trends in underlying causes and valve involvement.
- To assess changes in short-term fatality rates.
Main Methods:
- Retrospective cohort study using strict case identification criteria.
- Analysis of medical records for residents of Olmsted County, Minnesota (1950-1981).
- Age- and sex-adjusted incidence rate calculation per 100,000 person-years.
Main Results:
- Mean annual incidence was 3.8/100,000 person-years (total cases) and 3.2 (definite/probable cases).
- Incidence rates showed fluctuations across decades but remained relatively stable overall.
- Rheumatic heart disease decreased as an underlying cause, replaced by prosthetic valve endocarditis; 60-day fatality decreased significantly from 46% to 22-26%.
Conclusions:
- Endocarditis incidence in Olmsted County was relatively constant from 1950-1981.
- A shift in underlying pathology from rheumatic heart disease to prosthetic valves occurred.
- Improved diagnostic and treatment strategies led to a substantial reduction in early mortality.