The Ankle-Brachial Index in the Elderly and Risk of Stroke, Coronary Disease, and Death: The Framingham Study

Background A low ankle-brachial index (ABI) is associated with an increased risk of death and cardiovascular disease. Limited data exist regarding the relation between a low ABI and stroke. We sought to examine the relation between a low ABI and stroke, coronary heart disease, and death in the elderly. Methods We examined 251 men and 423 women with a mean age of 80 years who had a Framingham Study examination from 1994 to 1995. A low ABI was defined as less than 0.9. Persons were followed up for 4 years for occurrence of stroke or transient ischemic attack, coronary disease, and death. Cox proportional hazards models were used to assess the relation between a low ABI and each outcome after adjusting for age, sex, and prevalent cardiovascular disease. Results A low ABI was detected in 20% of our sample. Only 18% of the participants with a low ABI reported claudication symptoms. One third of those with a normal ABI and 55% of those with a low ABI had cardiovascular disease at baseline. Results of multivariable Cox proportional hazards analysis demonstrated a statistically significant increase in the risk of stroke or transient ischemic attack in persons with a low ABI (hazards ratio, 2.0; 95% confidence interval, 1.1-3.7). No significant relation between a low ABI and coronary heart disease (hazards ratio, 1.2; 95% confidence interval, 0.7-2.1) or death (hazards ratio, 1.4; 95% confidence interval, 0.9-2.1) was observed. Conclusions A low ABI is associated with risk of stroke or transient ischemic attack in the elderly. These results need to be confirmed in larger studies.