title: Concordance between plasma apolipoprotein B levels and cholesterol indices among patients receiving statins and nonstatin treatment: Post-hoc analyses from the U.K. InPractice study.
abstract: BACKGROUND
  Apolipoprotein B (ApoB) is a superior predictor of low-density-lipoprotein (LDL) particle number and cardiovascular disease (CVD) risk compared with LDL-cholesterol (LDL-C) levels. Current evidence has shown a degree of discordance between LDL-C with ApoB levels among patients not receiving lipid-lowering therapy. The extent of this discordance among patients receiving LDL-lowering therapies however is less clear.
  
  
  METHODS
  We performed a post hoc analysis of the InPractice data looking at the concordance between LDL-C, non-high density lipoprotein-cholesterol (nonHDL-C) and total cholesterol with ApoB values. The study involved 786 high-risk CVD patients from 34 primary care centers initially treated with simvastatin (S) 40 mg at baseline subsequently randomized to adding ezetimibe 10 mg to S 40 mg (E/S40) or changed to atorvastatin (A) 40 mg or to rosuvastatin (R) 5-10 mg for 6 weeks.
  
  
  RESULTS
  At 6 weeks after treatment, the association between LDL-C and ApoB values for the different treatment regimes were similar; Pearson's correlation coefficients between LDL-C and ApoB were 0.84 (E/S40), 0.82 (A), and 0.83 (R). Overall, ApoB appeared to have a slightly greater correlation with nonHDL-C than with LDL-C across all treatment groups, for baseline and posttreatment values. The analysis of quintile frequencies showed a similar pattern; the proportion of patients who had values that fell in the same quintile post treatment for ApoB and LDL-C levels were 52.2% (E/S40), 44.5% (A), and 49.4% (R). Concordance between ApoB and nonHDL-C was 60.6% (E/S40), 62.4% (A), and 61.8% (R). Kappa analysis confirmed fair agreement between LDL-C and ApoB levels for all treatment groups; 0.59 (E/S40), 0.54 (A), and 0.56(R).
  
  
  CONCLUSIONS
  We showed that the association between ApoB and LDL-C is similar across different lipid-lowering treatment regimes, which suggests that the use of different lipid-lowering agent confers similar ability to predict ApoB levels. When determining CVD risk at an individual patient level, limitation exists when using LDL-C or nonHDL-C per se as risk markers. In the absence of ApoB measurement, we believe that information from both LDL-C and nonHDL-C should be used together to improve the estimation of residual CVD risk among patients who are already receiving lipid lowering therapy.
authors.affiliation: Department of Diabetes and Endocrinology, Sherwood Forest Hospitals Foundation Trust, Nottinghamshire, UK. iidris@aol.com
authors.forename: Iskandar
authors.initials: I
authors.lastname: Idris
authors.forename: Helen
authors.initials: H
authors.lastname: Tate
authors.forename: Azhar
authors.initials: A
authors.lastname: Ahmad
authors.forename: Terry
authors.initials: T
authors.lastname: McCormack
mesh_terms: D000368:Aged; D001055:Apolipoproteins B / Q000097:blood*; D000069059:Atorvastatin; D001384:Azetidines / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000188:drug therapy / Q000209:etiology; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D000069438:Ezetimibe; D005260:Female; D005464:Fluorobenzenes / Q000627:therapeutic use; D006538:Heptanoic Acids / Q000627:therapeutic use; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D006949:Hyperlipidemias / Q000150:complications / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D011743:Pyrimidines / Q000627:therapeutic use; D011758:Pyrroles / Q000627:therapeutic use; D000068718:Rosuvastatin Calcium; D019821:Simvastatin / Q000627:therapeutic use; D013449:Sulfonamides / Q000627:therapeutic use
chemical_list: D001055:Apolipoproteins B; D001384:Azetidines; D015415:Biomarkers; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D005464:Fluorobenzenes; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011743:Pyrimidines; D011758:Pyrroles; D013449:Sulfonamides; D000068718:Rosuvastatin Calcium; D000069059:Atorvastatin; D019821:Simvastatin; D000069438:Ezetimibe