Fetuin-A and kidney function in persons with coronary artery disease--data from the Heart and Soul Study.
BACKGROUND
Fetuin-A is a serum protein that inhibits ectopic vascular calcification and is present in lower concentrations in end-stage renal disease than in healthy controls. Whether fetuin-A concentrations are also lower in the setting of mild-to-moderate chronic kidney disease (CKD) is unknown.


METHODS
We evaluated the associations of several parameters of kidney function including measured 24 h urinary creatinine clearance (CrCl), estimated glomerular filtration rate (GFR) by the Mayo Clinic quadratic GFR equation (qGFR), serum cystatin-C concentrations, and urinary albumin-to-creatinine ratio with serum fetuin-A concentrations in 970 outpatients with coronary artery disease. We used general linear models to determine the adjusted mean fetuin-A concentrations within each kidney function category.


RESULTS
The mean age of the study sample was 67 years, 82% were male, 71% had hypertension and 26% had diabetes mellitus. In adjusted analysis, we observed no significant differences in mean fetuin-A concentrations across groups defined by CrCl, qGFR, or albumin-to-creatinine ratio groups. For example, adjusted mean fetuin-A concentrations were 0.66 g/l in participants with CrCl > 90, 60-90 and 45-60 ml/min/1.73 m(2), and 0.65 g/l in participants with CrCl < 45 ml/min/1.73 m(2). Higher serum cystatin-C (indicating worse kidney function) was associated with higher adjusted mean serum fetuin-A concentrations (lowest quartile 0.62 g/l, highest quartile 0.68 g/l; P for trend <0.001).


CONCLUSIONS
Among ambulatory patients with coronary artery disease, there is no evidence that mild-to-moderate CKD is associated with lower concentrations of serum fetuin-A compared with persons with normal renal function. The mechanisms explaining the association between CKD and vascular calcification remain elusive.
Ix
Joachim H
JH
Division of Nephrology, Department of Medicine, Box 0532, HSE 672, University of California, San Francisco, San Francisco, CA 94143-0532, USA. jix@medicine.ucsf.edu
Chertow
Glenn M
GM
Shlipak
Michael G
MG
Brandenburg
Vincent M
VM
Ketteler
Markus
M
Whooley
Mary A
MA
D000368:Aged; D000419:Albuminuria / Q000209:etiology; D015415:Biomarkers; D001798:Blood Proteins / Q000032:analysis* / Q000172:deficiency; D002118:Calcium / Q000097:blood; D002908:Chronic Disease; D015331:Cohort Studies; D015897:Comorbidity; D003327:Coronary Disease / Q000097:blood* / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology; D003404:Creatinine / Q000652:urine; D055316:Cystatin C; D015891:Cystatins / Q000097:blood; D048909:Diabetes Complications / Q000097:blood / Q000503:physiopathology; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006937:Hypercholesterolemia / Q000453:epidemiology; D006973:Hypertension / Q000097:blood / Q000453:epidemiology / Q000503:physiopathology; D007668:Kidney / Q000503:physiopathology*; D007674:Kidney Diseases / Q000097:blood* / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D010758:Phosphorus / Q000097:blood; D011446:Prospective Studies; D012495:San Francisco / Q000453:epidemiology; D060749:alpha-2-HS-Glycoprotein
C556354:AHSG protein, human; D015415:Biomarkers; D001798:Blood Proteins; C525030:CST3 protein, human; D055316:Cystatin C; D015891:Cystatins; D060749:alpha-2-HS-Glycoprotein; D010758:Phosphorus; D003404:Creatinine; D002118:Calcium