Association of albumin-creatinine ratio and cystatin C with change in ankle-brachial index: The multi-ethnic study of atherosclerosis (MESA)

Background: Low ankle-brachial index (ABI) is a reflection of atherosclerotic disease, and high ABI is an indicator of calcified vessels. The associations of albuminuria and cystatin C level with incidence of either low or high ABI are unknown. Study Design: Prospective longitudinal cohort study. Setting & Participants: MESA (Multi-Ethnic Study of Atherosclerosis) enrolled community-dwelling adults (N = 6,814) aged 45-84 years who were free of clinical cardiovascular disease at baseline. Predictors: Baseline albumin-creatinine ratio (ACR) and serum cystatin C level. Outcomes: Development of low (1.40) ABI using multinomial regression among persons with ABI of 0.90-1.40 at baseline. Results: During 9.8 years of follow-up, 221 and 89 participants progressed to low and high ABIs, respectively. Baseline ACR and cystatin C level were higher among progressors compared with nonprogressors. In multivariable analyses, doubling of ACR was associated with increased risk of progression to low (OR, 1.08; 95% CI, 0.99-1.20) and high (OR, 1.16; 95% CI, 1.01-1.32) ABIs. Compared to the lowest quintile, the highest quintile of ACR had a significantly increased risk of progression to low (OR, 1.79; 95% CI, 1.03-3.12) and high (OR, 2.76; 95% CI, 1.32-5.77) ABIs. Higher cystatin C levels were associated with progression to low (OR per 1-SD greater, 1.12; 95% CI, 1.00-1.26) but not high (OR per 1-SD greater, 1.01; 95% CI, 0.81-1.25) ABI, but the highest quintile of cystatin C was not associated independently with either outcome. Limitations: Single measure of albuminuria and low number of progressors to high ABI. Conclusions: In adults free of clinical cardiovascular disease, albuminuria was a strong independent risk factor for the development of both high and low ABIs, important and different measures of peripheral artery disease.