title: A cut-off value of plasma osteoprotegerin level may predict the presence of coronary artery calcifications in chronic kidney disease patients.
abstract: BACKGROUND
  Expression of bone proteins resulting from transdifferentiation of vascular smooth muscle cells into osteoblasts suggests that vascular calcifications are a bioactive process. Osteoprotegerin (OPG) could play a key role in bone-vascular calcification imbalance and could be a marker of vascular calcification extent and progression. The purpose of this study was to evaluate relationships between vascular risk biomarkers (including classic risk factors and OPG) and coronary artery calcification (CAC) extent in chronic kidney disease (CKD) patients and to establish within the markers the appropriate cut-off value to predict CAC.
  
  
  METHODS
  A total of 133 non-dialyzed CKD patients at various stages of kidney disease [75 males/58 females, median age: 69.9 (27.4-94.6)] were enrolled, excluding extrarenal replacement therapy patients. All underwent chest multidetector computed tomography for CAC scoring. Blood samples were collected for measurement of vascular risk markers (kidney disease, inflammation, nutrition, calcium phosphate and OPG). A potential relationship between CAC and these biological markers was investigated, and a receiver-operating characteristic (ROC) curve was designed thereafter to identify a cut-off value of involved markers that best predicted the presence of CAC.
  
  
  RESULTS
  After adjustment for age, diabetes, smoking and gender, among biological markers, only low-estimated glomerular filtration rate using Modification of Diet in Renal Disease [OR = 3.63 (1.10-12.02)], high FEPO(4) [OR = 3.99 (1.17-13.6)] and high OPG levels [OR = 8.54 (2.14-34.11)] were associated with the presence of CAC. A protective effect of 1.25(OH)(2) vitamin D [OR = 0.20 (0.05-0.79)] and LDL cholesterol [OR = 0.27 (0.08-0.94)] on CAC was also observed. ROC curve analysis showed that the OPG best cut-off value predicting CAC was 757.7 pg/mL.
  
  
  CONCLUSIONS
  These results suggest that a CAC increase is strongly associated with a plasma OPG increase in CKD patients. The values of OPG >757.7 pg/mL allow us to predict the presence of CAC in these patients.
authors: Laboratoire de Biochimie, CHRU Montpellier, F-34000 France; Univ Montpellier 1, Montpellier, F-34000 France.
authors: Marion
authors: M
authors: Morena
authors: Anne-Marie
authors: AM
authors: Dupuy
authors: Isabelle
authors: I
authors: Jaussent
authors: Hélène
authors: H
authors: Vernhet
authors: Gérald
authors: G
authors: Gahide
authors: Kada
authors: K
authors: Klouche
authors: Anne-Sophie
authors: AS
authors: Bargnoux
authors: Cécile
authors: C
authors: Delcourt
authors: Bernard
authors: B
authors: Canaud
authors: Jean-Paul
authors: JP
authors: Cristol
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D002114:Calcinosis / Q000097:blood / Q000209:etiology*; D002908:Chronic Disease; D003324:Coronary Artery Disease / Q000097:blood / Q000209:etiology*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000097:blood* / Q000150:complications; D008297:Male; D008875:Middle Aged; D053244:Osteoprotegerin / Q000097:blood*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors
chemical_list: D015415:Biomarkers; D053244:Osteoprotegerin