title: Time dependent changes in high density lipoprotein cholesterol and cardiovascular risk.
abstract: BACKGROUND
  High-density lipoprotein cholesterol (HDL-C) is a strong inverse predictor of cardiovascular events. The aim of the current study was to evaluate the correlation between changes in HDL-C and subsequent cardiovascular events.
  
  
  METHODS
  Study population comprised 13,037 subjects free of cardiovascular disease with a mean follow up of 6 ± 3 years. Low HDL-C was defined as < 40 mg/dl for men and <50mg/dl for women. Participants were divided into three groups based on HDL-C levels at the first and second baseline visits: persistently-low HDL-C (LL); persistently-high HDL-C (HH); and those with high HDL-C in a one visit only: intermittently high HDL-C (LH/HL). The primary endpoint was the first occurrence of a cardiovascular event.
  
  
  RESULTS
  A total of 529 (4.1%) incident events occurred during follow-up. HDL-C levels increased significantly between the two landmark visits (47.5 ± 12.6 vs. 48.1 ± 12.2, p<0.001). Kaplan-Meier survival analysis showed that the cumulative probability of cardiovascular events at 6 years was highest among subjects in the LL group (7.6%), and similar among LH/HL and HH groups (3.3% and 4%, respectively; log-rank p=0.001). Multivariate Cox regression analysis, with HDL-C as time-dependent covariate, showed that subjects with persistently low HDL-C during follow up experienced a 51% increased cardiovascular risk compared with subjects with persistently high HDL-C (p=0.026). Subjects with intermittently high HDL-C during follow up experienced similar risk to those with persistently high HDL-C (HR=1.02; p=0.89).
  
  
  CONCLUSIONS
  Variations in HDL-C levels during follow-up are associated with subsequent cardiovascular risk. Patients who retain low HDL-C levels are at the cardiovascular highest risk.
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Israel; Department of Internal Medicine "E", Tel-Aviv Medical Center, Israel.
authors.forename: Assi
authors.initials: A
authors.lastname: Milwidsky
authors.affiliation: Department of Internal Medicine C, Sheba Medical Center, Israel; Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Israel; Sackler School of Medicine, Tel-Aviv University, Israel.
authors.forename: Shaye
authors.initials: S
authors.lastname: Kivity
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Israel.
authors.forename: Eran
authors.initials: E
authors.lastname: Kopel
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Israel; Sackler School of Medicine, Tel-Aviv University, Israel.
authors.forename: Robert
authors.initials: R
authors.lastname: Klempfner
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Israel.
authors.forename: Anat
authors.initials: A
authors.lastname: Berkovitch
authors.affiliation: Institute for Medical Screening, Sheba Medical Center, Israel.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Segev
authors.affiliation: Department of Internal Medicine C, Sheba Medical Center, Israel; Sackler School of Medicine, Tel-Aviv University, Israel.
authors.forename: Yechezkel
authors.initials: Y
authors.lastname: Sidi
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Israel; Sackler School of Medicine, Tel-Aviv University, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Goldenberg
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Israel; Pinchas Borenstein Talpiot Medical Leadership Program, Sheba Medical Center, Israel. Electronic address: Elad.Maor@sheba.health.co.il.
authors.forename: Elad
authors.initials: E
authors.lastname: Maor
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology*; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D013997:Time Factors
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL
keywords: Cardiovascular risk; HDL cholesterol; Time dependent changes