Anticoagulation in the Elderly
This review will address the general approach to the management of the typical elderly patient requiring anticoagulation. Most of the data has been derived from studies of patients with nonvalvular atrial fibrillation. Data from postmyocardial infarction trials have also been included. A practical clinical approach to anticoagulation in the elderly is described. Emphasis has been placed on maximizing the benefit and reducing the risk of anticoagulation in the rapidly expanding group of elderly patients aged ≥75 who are at the greatest risk of stroke and are likely to benefit the most from antithrombotic therapy.
Atrial fibrillation (AF) is the most common arrhythmia found in adults, and it is twice as common as all other arrhythmias combined. There are an estimated 2.2 million people in the United States with atrial fibrillation. This number is projected to increase 2.5-fold to more than 5.6 million by the year 2050. The median age of patients with AF is approximately 75 years. The prevalence of AF increases rapidly with age. In individuals aged 50-59 years it occurs in only 0.5% of the population. Between 60-69 years, prevalence is about 3.8% for men and slightly less for women. In the age group above 70, the estimated prevalence is 9%. Even though the prevalence is higher in men, the absolute number of women and men with AF is approximately equal because there are more women than men in the older age group.
In low mortality populations, life expectancy has now risen to between 75 and 80 years. Persons 65 years of age and over make up almost 13% of the total population and this percentage is continuing to rise. Persons reaching age 65 can now expect to live an additional 17 years15 years for men and 19 years for women. Moreover in the United States the baby-boomer generation is now aging. Thus, the number of patients over age 75 with AF is expected to increase dramatically over the next several decades.
In addition to causing hemodynamic compromise, AF is a significant marker for both a higher incidence of stroke and increased mortality. In the Framingham Study, the risk of stroke was 5.6 times greater than comparably aged patients in sinus rhythm and rose from 1.5% in the age group 50-59 to 23.5% in the age group 80-89. The risk of stroke seems independent of whether AF is constant or intermittent.