title: Classification of chronic kidney disease biomarkers to predict coronary artery calcium.
abstract: OBJECTIVE
  The link between CKD and CAC has been mostly established by studies of patients who have abnormally high phosphorus levels and advanced CKD or end-stage renal disease. The aim of this study was to examine if there are distinct trajectory classes of serum phosphorus (controlling for eGFR) that are associated CAC in a relatively healthy, community sample.
  
  
  METHODS
  Phosphorus and eGFR were classified as a combined biomarker variable with 4 trajectory classes by growth mixture modeling. This classification variable was subsequently used to predict CAC as both a binary (i.e., onset) and continuous (i.e., accumulation) outcome using a two-part growth model.
  
  
  RESULTS
  Membership in one class of phosphorus trajectory versus the next lowest level was associated with a 97.9 Agatston unit increase in CAC (p <.001). The magnitude of this finding is similar in size as some primary risk factors for cardiovascular disease, including a 55.3 Agatston unit (p <.001) increase associated with age, and a--75.1 Agatston unit (p <.001) decrease associated with female gender.
  
  
  CONCLUSIONS
  Classification of phosphorus trajectories provides further definition for prediction of CAC within the conventional 'normal' range. Classifying trajectories may help determine clinically-relevant thresholds for interventions aimed at phosphorus reduction.
authors: Washington State University, College of Nursing, Washington State University, Spokane, WA, USA. smcpherson05@wsu.edu
authors: Sterling
authors: S
authors: McPherson
authors: Celestina
authors: C
authors: Barbosa-Leiker
authors: Robert
authors: R
authors: Short
authors: Katherine R
authors: KR
authors: Tuttle
mesh_terms: D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000378:metabolism*; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000453:epidemiology*; D003331:Coronary Vessels / Q000378:metabolism*; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010758:Phosphorus / Q000097:blood* / Q000145:classification*; D011237:Predictive Value of Tests; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D012307:Risk Factors; D012737:Sex Factors; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers; D010758:Phosphorus; D002118:Calcium