Relationship between kidney function and risk of asymptomatic peripheral arterial disease in elderly subjects

Abstract

Limited data exist regarding the relationship between kidney function and incident asymptomatic peripheral arterial disease (PAD). The study population consisted of 2881 participants of the Intervention Project on Cerebrovascular Diseases and Dementia in the Community of Ebersberg, Bavaria, a community-based cohort of elderly individuals. Kidney function was calculated as creatinine clearance (Ccr) estimated by the Cockcroft-Gault formula. Incident PAD was defined as a new onset of ankle-brachial index < 0.9 assessed at regular examinations among those with an ankle brachial pressure index (ABPI) ≥ 0.9 at baseline. Relative risks (RR) for PAD were compared across declining kidney function quartiles. Mean serum concentration of creatinine and Ccr were 0.82 ± 0.31 mg/dL and 78 ± 21 mL/min/1.73 m(2). After 6 years of follow-up, 478 (17%) participants developed incident asymptomatic PAD. After adjustment for demographic factors and cardiovascular risk factors, lower Ccr quartiles were directly associated with a higher risk of PAD. Compared with participants in quartile 1 (> 89 mL/min/1.73 m(2)), the adjusted RR (95% CI) for PAD were 1.01 (0.88-1.19) for quartile 2 (75-89 mL/min/1.73 m(2)), 1.05 (0.93-1.23) for quartile 3 (64-75 mL/min/1.73 m(2)) and 1.10 (1.01-1.44) for quartile 4 (< 64 mL/min/1.73 m(2); P = 0.009 for trend). Cardiovascular events as a function of baseline Ccr and incident PAD showed that most vascular events occurred in participants with Ccr < 60 mL/min/1.73 m(2) at baseline and incident PAD (log-rank test, P = 0.0018). Lower kidney function is associated with incident asymptomatic PAD. In addition, the combination of impaired kidney function and incident PAD better predicts cardiovascular outcomes.