Submitted to: Journal of the American Heart Association
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/20/2013
Publication Date: 11/12/2013
Citation: Mcdermott, M.M., Applegate, W.B., Bonds, D.E., Buford, T.W., Church, T., Espeland, M.A., Gill, T.M., Guralnik, J.M., Haskell, W., Lovato, L.C., Pahor, M., Pepine, C.J., Reid, K.F., Newman, A. 2013. Ankle brachial index values, leg symptoms, and functional performance among community-dwelling older men and women in the lifestyle interventions and independence for elders study. Journal of the American Heart Association. 2(6):e000257. DOI: 10.1161/JAHA.113.000257. Interpretive Summary: Lower extremity peripheral artery disease (PAD) affects eight million men and women in the United States and will be increasingly common as the relative longevity of the U.S. population increases. PAD can be detected easily and non-invasively with the ankle brachial index (ABI), which is the ratio of systolic blood pressures in the lower and upper extremities. While PAD is often asymptomatic or can present with unusual leg symptoms, the prevalence and significance of low normal and abnormal ankle brachial index (ABI) values in a community dwelling population of sedentary, older individuals is unknown. The purpose of this study was to describe the prevalence of categories of definite PAD, borderline PAD, low-normal ABI and no PAD and their association with lower extremity functional performance in a large cohort of older men and women from the Lifestyle Interventions and Independence for Elders (LIFE) study. This study found of 1,566 participants, 220 (14%) had definite PAD, 250 (16%) had borderline PAD, 509 (33%) had low normal ABI, and 587 (37%) had no PAD. Among those with definite PAD, 65% had no symptoms. Among participants with and without PAD, lower ABI values were also associated with longer 400-meter walk time and overall slower walking speed.
Technical Abstract: The prevalence and significance of low normal and abnormal ankle brachial index (ABI) values in a community dwelling population of sedentary, older individuals is unknown. We describe the prevalence of categories of definite peripheral artery disease (PAD), borderline ABI, low-normal ABI and no PAD and their association with lower extremity functional performance in the LIFE Study population. Participants age 70-89 in the LIFE Study underwent baseline measurement of the ABI, 400-meter walk, and four-meter walking velocity. Participants were classified as follows: definite PAD (ABI < 0.90), borderline PAD (ABI 0.90 to 0.99), low normal ABI (ABI 1.00 to 1.09) and no PAD (ABI 1.10-1.40). Of 1,566 participants, 220 (14%) had definite PAD, 250 (16%) had borderline PAD, 509 (33%) had low normal ABI, and 587 (37%) had no PAD. Among those with definite PAD, 65% were asymptomatic. Adjusting for age, sex, race, body mass index, smoking, and comorbidities, lower ABI was associated with longer mean 400-meter walk time: (definite PAD= 533 seconds; borderline PAD=514 seconds, low normal ABI=503 seconds, and no PAD=498 seconds (P <0.001)). Among asymptomatic participants with and without PAD, lower ABI values were also associated with longer 400-meter walk time (P<0.001) and slower walking velocity (P=0.042). Among older community-dwelling men and women, 14% had PAD and 49% had borderline or low normal ABI values. Lower ABI values were associated with greater functional impairment, suggesting that lower extremity atherosclerosis may be a common preventable cause of functional limitations in older people.