Low Ankle-Brachial Index Associated With Rise in Creatinine Level Over Time

BACKGROUND: A low ankle-brachial index (ABI) predicts risk of cardiovascular death, myocardial infarction, peripheral arterial disease events, and stroke. However, it is unknown whether a low ABI also predicts a decline in renal function. METHODS: We examined the association between ABI and change in serum creatinine level over time among 13 655 participants in the Atherosclerosis Risk in Communities (ARIC) study who underwent serum creatinine and ABI measurement at baseline and also underwent serum creatinine measurement 3 years later at the second study visit. The study outcome was a 50% rise in serum creatinine level from baseline to the second study visit. RESULTS: Overall, 0.48% of participants with an ABI of 1 or higher, 0.9% of participants with an ABI between 0.9 and 0.99, and 2.16% of participants with an ABI lower than 0.9 experienced a 50% or greater increase in serum creatinine level. In multivariate analysis, participants with an ABI lower than 0.9 were still more than twice as likely as those in the referent category (ABI > or = 1) to experience an increase in serum creatinine level (odds ratio 2.5; 95% confidence interval, 1.1-5.7) (P = .04), and a linear trend in the incidence of worsening renal function was noted across ABI categories (P = .02). Analyses excluding participants with renal insufficiency, diabetes, and hypertension at baseline all produced similar results. CONCLUSION: In addition to known associations of the ABI with stroke, myocardial infarction, peripheral arterial disease events, and cardiovascular death, a low ABI also predicts an increase in serum creatinine level over time.