title: Comparison of equations for the calculation of LDL-cholesterol in hospitalized patients.
abstract: BACKGROUND
  The Friedewald equation is widely used to calculate LDL-C for cardiovascular risk prediction but is less accurate with comorbidities and extreme lipid values. Several novel formulae have been reported to outperform the Friedewald formula.
  
  
  METHODS
  We examined 14,219 lipid profiles and evaluated four formulae (Friedewald, Chen, de Cordova, Hattori) and compared these to direct measurement of LDL-C across various triglyceride (TG), total cholesterol (TC) and HDL-cholesterol (HDL-C) ranges using Beckman reagents and instruments. Linear regression and ROC analysis were performed.
  
  
  RESULTS
  The de Cordova formula showed a high correlation with directly measured LDL-C (r=0.90, P<0.001), comparable to the Friedewald calculated values for directly measured LDL-C (r=0.95, P<0.001). The de Cordova formula was favorable in some ranges of HDL, TC and the lowest TG range (r=0.97, P<0.001) but performed least well in comparison with the three other LDL-C calculations (AUC=0.8331), demonstrating inconsistent bias. The Chen formula performed better than Friedewald (AUC=0.9049). The Hattori formula outperformed all formulae including Friedewald over various ranges of lipid values (AUC=0.9097).
  
  
  CONCLUSIONS
  We observe favorable correlations of the de Cordova formula with Friedewald at low TG values. However, the Hattori formula appears to be best for application in hospitalized patients, even at extreme lipid values.
authors: Department of Chemical Pathology, University of Pretoria, Faculty of Health Sciences and NHLS Tshwane Academic Division, Steve Biko Academic Hospital, Pretoria, South Africa.
authors: J
authors: J
authors: Martins
authors: Medical Research Council, South Africa.
authors: S A S
authors: SA
authors: Olorunju
authors: Department of Chemical Pathology, University of Pretoria, Faculty of Health Sciences and NHLS Tshwane Academic Division, Steve Biko Academic Hospital, Pretoria, South Africa.
authors: L M
authors: LM
authors: Murray
authors: Department of Chemical Pathology, University of Pretoria, Faculty of Health Sciences and NHLS Tshwane Academic Division, Steve Biko Academic Hospital, Pretoria, South Africa. Electronic address: tspillay@gmail.com.
authors: T S
authors: TS
authors: Pillay
mesh_terms: D005260:Female; D006760:Hospitalization; D006801:Humans; D016014:Linear Models; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies
chemical_list: D008077:Lipoproteins, LDL
keywords: Friedewald equation; Hospitalized patients; LDL-cholesterol