Mild renal dysfunction as a non-traditional cardiovascular risk factor?-Association of cystatin C-based glomerular filtration rate with flow-mediated vasodilation.

Objective: Chronic kidney disease, at least in its advanced stages, can be regarded as a non-traditional cardiovascular risk factor. The purpose of this study was to evaluate whether early stages of renal dysfunction are associated with flow-mediated vasodilatation, as an early marker of the atherosclerotic disease process.

Methods: In 1515 subjects (753 females) from the population-based Study of Health in Pomerania, the relationship between flow-mediated vasodilatation of the brachial artery (cuff occlusion of the forearm for 5 min) and glomerular filtration rate, estimated on the basis of serum cystatin C levels, was analyzed under consideration of various cardiovascular risk factors.

Results: Flow-mediated vasodilatation was 5.75 + or - 0.16% in women and 4.29+/-0.12% in men (mean + or - SEM). Glomerular filtration rate amounted to 94.2 + or - 0.7 ml/min/1.73 m(2), with 8.1% subjects with glomerular filtration rate < or = 60 ml/min/1.73 m(2). Flow-mediated vasodilatation significantly correlated with glomerular filtration rate in the entire population (r=0.237, p<0.001), in women (r=0.224, p<0.001) and in men (r=0.168, p<0.001). Adjusting for age and multiple cardiovascular risk factors and also for high-sensitive C-reactive protein levels revealed a significant association of flow-mediated vasodilatation and glomerular filtration rate in women (p=0.01), but not in men, with similar results when the analyses were restricted to individuals with glomerular filtration rate >60 ml/min/1.73 m(2).

Conclusion: Mild reduction in renal function is associated with alterations in endothelial function in females. Hence, very mild alterations in kidney function may also be regarded as a cardiovascular risk factor at least in women.