Infective endocarditis. Olmsted County, Minnesota, 1950 through 1981

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.