title: Iron deficiency: a novel risk factor of recurrence in patients after unprovoked venous thromboembolism.
abstract: BACKGROUND
  Patients with unprovoked venous thromboembolism (VTE) are at high risk of recurrence; however, its predictors remain largely unknown. There is evidence that iron is implicated in the pathophysiology of thrombosis.
  
  
  OBJECTIVE
  We aimed to investigate whether iron deficiency (ID) affects the risk of recurrence in patients after unprovoked VTE.
  
  
  METHODS
  In this prospective cohort study, we examined 229 consecutive patients aged 65 years or younger with the first-ever episode of unprovoked VTE within 6 to 12 months prior to enrollment. The exclusion criteria were as follows: hemoglobin levels of less than 11 g/dl, heart failure, diabetes, cancer, serum creatinine levels exceeding 120 μM, and previous or current use of iron or erythropoiesisstimulating agents, or both. ID was defined as serum ferritin levels below 30 μg/l. Recurrent VTE was recorded during a 24-month follow-up.
  
  
  RESULTS
  ID was observed in 47 patients (21%). In a multivariate regression model, the presence of ID was associated with female sex, elevated C-reactive protein (CRP), anemia and reduced hemoglobin levels (all P <0.05). In a multivariate model, the presence of ID (or low serum ferritin levels) and elevated CRP levels, but not anemia, predicted VTE recurrence during 24 months. The hazard ratio adjusted for CRP and the presence of anemia was 3.17 for ID (95% confidence interval [CI], 1.20-8.38; P = 0.02) and 0.64 for serum ferritin levels (95% CI, 0.43-0.94; P = 0.02).
  
  
  CONCLUSIONS
  ID may represent a novel risk factor for VTE recurrence in young and middle-aged patients following an unprovoked episode.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Potaczek
authors.forename: Ewa A
authors.initials: EA
authors.lastname: Jankowska
authors.forename: Ewa
authors.initials: E
authors.lastname: Wypasek
authors.forename: Anetta
authors.initials: A
authors.lastname: Undas
mesh_terms: D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D006801:Humans; D000090463:Iron Deficiencies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012737:Sex Factors; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology
chemical_list: D002097:C-Reactive Protein