San Diego, CA - Individuals with a high ankle-brachial index (ABI) are at greater risk for developing foot ulcers and neuropathy and score lower on some physical functioning quality-of-life (QoL) testing domains, a new study has shown [1]. This new evidence, say investigators, suggests clinicians should consider the entire range of ABI values when evaluating a patient for lower-extremity arterial disease.

Publishing their findings in the April 1, 2008 issue of the Journal of the American College of Cardiology, Dr Matthew Allison (University of California, San Diego) and colleagues note that individuals with an ABI <0.90 have a greater risk of incident cardiovascular disease morbidity and mortality, but that using <0.90 as a cutoff can lead to underdiagnosis of systemic atherosclerosis. Previous studies, they write, have shown that individuals with an ABI >1.30 have higher levels of cardiovascular risk factors, suggesting a higher ABI index is associated with cardiovascular disease morbidity. They add that there is a gap in the literature on the relationship between a high ABI and measures that describe the health impact of vascular disease.

To determine the risk factors, comorbid cardiovascular disease conditions, and QoL associated with a higher ABI, Allison and colleagues collected data from 350 community-based clinics and identified 4420 patients with an ABI between 0.90 and 1.40 and 296 subjects with an ABI >1.40 in at least one leg. Subjects were, on average, 70 years of age, and more than 80% were hypertensive. In a logistic regression model, diabetes, male gender, and waist circumference were associated with an ABI >1.40, while smoking and dyslipidemia were inversely associated with a high ABI.

As noted, those with an ABI >1.40 had a significantly higher prevalence of foot ulcers after adjustment for age, gender, race, smoking, diabetes, hypertension, dyslipidemia, and body-mass index (OR 2.67, 95% CI 1.42-5.02). There were "marginally significant associations" of high ABI with congestive heart failure, stroke, and neuropathy, but investigators say that although the findings were adjusted there is a possibility of residual confounding. Those with a high ABI also scored lower on the physical-component scale of the QoL SF-36 and lower on the walking-distance domain of the walking impairment questionnaire.

The group notes that diabetic patients were at higher risk for a low and high ABI. In addition to alerting clinicians to the clinical significance of the entire range of ABI values, the findings, say investigators, point to the need for further studies of the mechanism that underlies the development of a high ABI. In addition, the results possibly suggest the use of "aggressive risk-factor management of these patients in an effort to improve QoL while decreasing the risk for untoward CVD events."