Ankle-brachial index and physical function in older individuals: The Atherosclerosis Risk in Communities (ARIC) study

Abstract

Background and aims: Most prior studies investigating the association of lower extremity peripheral artery disease (PAD) with physical function were small or analyzed selected populations (e.g., patients at vascular clinics or persons with reduced function), leaving particular uncertainty regarding the association in the general community.

Methods: Among 5262 ARIC participants (age 71-90 years during 2011-2013), we assessed the cross-sectional association of ankle-brachial index (ABI) with the Short Physical Performance Battery (SPPB) score (0-12), its individual components (chair stands, standing balance, and gait speed) (0-4 points each), and grip strength after accounting for potential confounders, including a history of coronary disease, stroke, or heart failure.

Results: There were 411 participants (7.8%) with low ABI ≤0.90 and 469 (8.9%) participants with borderline low ABI 0.91-1.00. Both ABI ≤0.90 and 0.91-1.00 were independently associated with poor physical function (SPPB score ≤6) compared to ABI 1.11-1.20 (adjusted odds ratio 2.10 [95% CI 1.55-2.84] and 1.86 [1.38-2.51], respectively). The patterns were largely consistent across subgroups by clinical conditions (e.g., leg pain or other cardiovascular diseases), in every SPPB component, and for grip strength. ABI >1.3 (472 participants [9.0%]), indicative of non-compressible pedal arteries, was related to lower physical function as well but did not necessarily reach significance.

Conclusions: In community-dwelling older adults, low and borderline low ABI suggestive of PAD were independently associated with poorer systemic physical function compared to those with normal ABI. Clinical attention to PAD as a potential contributor to poor physical function is warranted in community-dwelling older adults.

Keywords: Aging; Peripheral artery disease; Physical function.

Fig. 1. Association of ABI with total score of the Short Physical Performance Summary (SPPB)

Adjusted SPPB score (A) and adjusted odds ratio of low SPPB score (≤ 6) (B) according to ABI categories. The results were adjusted for age, race, sex, education, smoking, alcohol, body mass index, antihypertensive drugs, systolic blood pressure, lipid lowering drugs, total and HDL cholesterols, diabetes, and history of coronary disease, heart failure, and stroke. * Indicates statistical significance with ABI 1.11-1.20 as the reference.

Fig. 2. Association of ABI with each component of the Short Physical Performance Summary (SPPB)

Adjusted score of each component in the SPPB ((A) [chair stand score], (C) [standing balance score], and (E) [gait speed score]) and adjusted odds ratio of having low score (≤2) of each component ((B) [chair stand score], (D) [standing balance score], and (F) [gait speed score]) according to ABI categories. *Indicates statistical significance with ABI 1.11-1.20 as the reference.

Fig. 2. Association of ABI with each component of the Short Physical Performance Summary (SPPB)

Adjusted score of each component in the SPPB ((A) [chair stand score], (C) [standing balance score], and (E) [gait speed score]) and adjusted odds ratio of having low score (≤2) of each component ((B) [chair stand score], (D) [standing balance score], and (F) [gait speed score]) according to ABI categories. *Indicates statistical significance with ABI 1.11-1.20 as the reference.

Fig. 3. Adjusted odds ratio of low SPPB score (≤6) according to lower ABI ≤1.00 vs. 1.01-1.30 by demographic and clinical subgroups

The results were adjusted for age, race, sex, education, smoking, alcohol, body mass index, antihypertensive drugs, systolic blood pressure, lipid lowering drugs, total and HDL cholesterols, diabetes, and history of coronary disease, heart failure, and stroke, as appropriate.