title: Validation of the Friedewald formula for the determination of low-density lipoprotein cholesterol in renal transplant recipients.
abstract: In large patient populations, it has been established that calculated (c) and measured (m) plasma levels of low-density lipoprotein cholesterol (LDL-C) were comparable, but this issue is not known to be tested in renal transplant recipients (RTRs). Herein we aimed to compare the plasma levels of LDL-C that was calculated by Friedewald formula (FF) and direct measurement in RTRs.
  
  
  METHODS
  LDL-C was measured by direct method and by FF in 193 fasting venous blood samples obtained from 103 RTRs. Patients had triglyceride (TG) levels <400 mg/dL. Patients were treated with prednisolone, calcineurin inhibitors (CNIs), and/or sirolimus and everolimus.
  
  
  RESULTS
  The mean plasma levels of LDL-C for calculated and direct measurement were 100.81 +/- 32.79 mg/dL and 107.82 +/- 33.23 mg/dL, respectively (p < 0.01). The differences between cLDL-C and mLDL-C were similar according to usage of angiotensin receptor blockers (ARB)/angiotensin-converting enzyme inhibitors (ACEI), CNI, or mammalian target of rapamycin inhibitor (mTOR), tacrolimus or cyclosporine, and serum creatinine levels. mLDL-C and cLDL (FF) were highly correlated (r = 0.977). The mLDL-C level was calculated by following formula: LDL-C = 8.018 + (0.99 x FF cLDL-C) and the mean difference was 0 for last formula.
  
  
  CONCLUSIONS
  The LDL-C can be calculated by the following formula: LDL-C = 8.018 + (0.99 x FF LDL-C). The coefficient of determination correlation (r) for this regression was 0.977, which indicates that the calculated LDL-C levels can be used in RTRs with TG lower than 400 mg/dL. mLDL-C was significantly higher than cLDL-C. We observed that difference between cLDL-C and mLDL-C levels were not affected by serum creatinine levels and usage of CNIs, sirolimus, everolimus, ACEI, and ARB in RTRs.
authors.affiliation: Faculty of Medicine, Department of Nephrology, Cukurova University, Adana, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Balal
authors.forename: Saime
authors.initials: S
authors.lastname: Paydas
authors.forename: Tamer
authors.initials: T
authors.lastname: Inal
authors.forename: Erkan
authors.initials: E
authors.lastname: Demir
authors.forename: Cemal
authors.initials: C
authors.lastname: Kurt
authors.forename: Yasar
authors.initials: Y
authors.lastname: Sertdemir
mesh_terms: D000328:Adult; D008078:Cholesterol, LDL / Q000097:blood*; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation; D008297:Male; D012044:Regression Analysis
chemical_list: D008078:Cholesterol, LDL; D007166:Immunosuppressive Agents; D003404:Creatinine