Cystatin C--a marker of peripheral atherosclerotic disease?

Unlabelled: It has been suggested that Cystatin C, besides its function as a marker of glomerular filtration, could be an independent marker of cardiovascular disease. However, studies on this topic are few and results have been indecisive. Our aim was to further investigate the subject of Cystatin C as an independent marker of peripheral atherosclerotic disease.
Method: Blood samples were analysed for serum Cystatin C, IL6, CRP and creatinine in 103 males with peripheral arterial disease (PAD) and 96 controls matched for age and sex. Creatinine clearance (CCr) was calculated according to Cockcroft's formula and estimated glomerular filtration rate (eGFR) was calculated according to MDRD formula.
Results: Cystatin C-concentration was higher in PAD-patients compared to controls; 1.09+/-0.40 vs. 0.95+/-0.17 mg/L (p<0.01). There was no difference in CCr; 81+/-27 vs. 82+/-22 mL/min or eGFR; 76+/-21 vs. 79+/-14 mL/min. Cystatin C correlated to CCr, logIL-6 and logCRP in both patients (r=-0.60, p<0.001), (r=0.35, p<0.001) and (r=0.30, p<0.01) and controls (-0.44, p<0.001), (0.38, p<0.001) and (r=0.32, p<0.01), respectively. In an analysis of covariance, corrected for difference in eGFR, Cystatin C remained higher in PAD-patients compared to controls; 1.09 (C.I. 1.04-1.14) vs. 0.96 (C.I. 0.90-1.01).
Conclusion: Cystatin C-concentration, corrected for differences in eGFR, IL-6 and CRP values, is higher in PAD-patients compared to controls. Our finding suggests that Cystatin C may be an independent marker of atherosclerotic disease apart from its relation to kidney function.