title: Apolipoprotein M and the risk of unprovoked recurrent venous thromboembolism.
abstract: BACKGROUND
  Apolipoprotein M (ApoM) protects against atherosclerosis; however, it is unknown whether it also protects against recurrent venous thromboembolism (VTE).
  
  
  METHODS
  Patients in the Malmö Thrombophilia Study (MATS) were followed post-anticoagulant treatment until the diagnosis of recurrent VTE or the end of the study (mean follow-up 36 months). Among patients with a first episode of unprovoked VTE, we identified 43 patients (9.7%) with recurrent VTE during the follow-up period. Three age- and sex-matched control subjects without recurrent VTE were selected for each case (n = 129). Plasma levels of ApoM were quantified by a sandwich ELISA method.
  
  
  RESULTS
  Among all patients, the plasma levels (mean ± SD) of ApoM were not significantly different between patients with recurrent (0.70 ± 0.2) and non-recurrent VTE (0.74 ± 0.2), p = 0.2. However, after stratification of data according to gender, male patients with recurrent VTE showed significantly (p=0.02) lower ApoM levels (0.63 ± 0.2) as compared to those with non-recurrent VTE (0.74 ± 0.2). No significant differences in ApoM levels were found between recurrent (0.8 ± 0.2) and non-recurrent VTE (0.75 ± 0.2) in female patients, p = 0.3. Cox-regression analysis showed that the risk of recurrent VTE was 0.98 (95% CI, 0.96-0.99) for each 0.01 μM increase in ApoM level in male patients (p = 0.042), and this risk remained unchanged after adjusting for inherited thrombophilia and body mass index (p = 0.027). ApoM levels were not associated with the risk of recurrent VTE in female patients.
  
  
  CONCLUSIONS
  Our results show that levels of ApoM in recurrent VTE may differ according to gender and lower levels of ApoM may predict VTE recurrence in male patients.
authors.affiliation: Center for Primary Health Care Research, Department of Clinical Sciences, Skåne University Hospital, Lund University, Sweden. Electronic address: ashfaque.memon@med.lu.se.
authors.forename: Ashfaque A
authors.initials: AA
authors.lastname: Memon
authors.affiliation: Center for Primary Health Care Research, Department of Clinical Sciences, Skåne University Hospital, Lund University, Sweden; Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Jan
authors.initials: J
authors.lastname: Sundquist
authors.affiliation: Center for Primary Health Care Research, Department of Clinical Sciences, Skåne University Hospital, Lund University, Sweden.
authors.forename: Bengt
authors.initials: B
authors.lastname: Zöller
authors.affiliation: Center for Primary Health Care Research, Department of Clinical Sciences, Skåne University Hospital, Lund University, Sweden.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Laboratory Medicine, Skåne University Hospital, Lund University, Sweden.
authors.forename: Björn
authors.initials: B
authors.lastname: Dahlbäck
authors.affiliation: Department of Coagulation Disorders, Skåne University Hospital, Lund University, Sweden.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Svensson
authors.affiliation: Center for Primary Health Care Research, Department of Clinical Sciences, Skåne University Hospital, Lund University, Sweden; Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, CA, United States.
authors.forename: Kristina
authors.initials: K
authors.lastname: Sundquist
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage; D001053:Apolipoproteins / Q000097:blood*; D000075243:Apolipoproteins M; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012307:Risk Factors; D012737:Sex Factors; D054556:Venous Thromboembolism / Q000097:blood* / Q000473:pathology
chemical_list: C400523:APOM protein, human; D000925:Anticoagulants; D001053:Apolipoproteins; D000075243:Apolipoproteins M; D054834:Lipocalins
keywords: Apolipoprotein M; Recurrence; Risk factors; Venous thrombosis