Effect of hormone replacement therapy on the validity of the Friedewald equation in postmenopausal women: the postmenopausal estrogen/progestins interventions (PEPI) trial.
The Friedewald equation is often used to estimate low-density lipoprotein cholesterol (LDL-C). Hormone therapy is known to raise triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) and alter lipid contents of lipoproteins. We compared Friedewald estimated LDL-C to measured LDL-C in PEPI participants on placebo or four different hormone treatment groups. At baseline, the 0.2 coefficient for triglyceride (TG) was accurate for all five treatment groups. Among women who took >80% of their pills and whose TG was <4.5 mmol/l (400 mg/dl), LDL-C was underestimated for 69-82% of the participants in the active treatment groups, compared to 50% in the placebo group. After 3 years of therapy, the TG coefficient that offered a better fit of the Friedewald equation in the active treatment groups was 0.39 for the equation in mmol/l (0.17 for the equation in mg/dl). Using this coefficient is clearly warranted for greater accuracy in research studies.
Legault
C
C
Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1063, USA. clegault@rc.phs.wfubmc.edu
Stefanick
M L
ML
Miller
V T
VT
Marcovina
S M
SM
Schrott
H G
HG
D000465:Algorithms; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood*; D015243:Cholesterol, VLDL / Q000097:blood; D004359:Drug Therapy, Combination; D004966:Estrogens, Conjugated (USP) / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy; D006801:Humans; D017258:Medroxyprogesterone Acetate / Q000627:therapeutic use; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood* / Q000187:drug effects; D011374:Progesterone / Q000627:therapeutic use; D045167:Progesterone Congeners / Q000627:therapeutic use; D011372:Progestins / Q000627:therapeutic use*; D015203:Reproducibility of Results; D014280:Triglycerides / Q000097:blood*
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D015243:Cholesterol, VLDL; D004966:Estrogens, Conjugated (USP); D045167:Progesterone Congeners; D011372:Progestins; D014280:Triglycerides; D011374:Progesterone; D017258:Medroxyprogesterone Acetate