title: Venous thromboembolism related to warm autoimmune hemolytic anemia: a case-control study.
abstract: BACKGROUND
  The risk of venous thromboembolism (VTE) during warm autoimmune hemolytic anemia (wAIHA) is apparent in several published series. Unlike proximate disorders (autoimmune thrombocytopenia, non-immune hemolytic diseases) little is known about the presentation and risk factors for VTE in this setting.
  
  
  OBJECTIVE
  To determine the frequency, presentation and risk factors for VTE associated with wAIHA.
  
  
  METHODS
  We performed a single center retrospective study of adult patients (>18years) followed for wAIHA between 2009 and 2013. VTE risk factors were systematically assessed. The characteristics of patients with or without VTE were compared. VTE presentation and precipitating factors were analyzed. The Padua VTE risk score was calculated in each case.
  
  
  RESULTS
  Forty patients were included. wAIHA was idiopathic in 24 patients (60%). Twelve patients (30%) had Evans syndrome. Mean lowest hemoglobin level was 6.6g/dl [3.7-11.5]. Eight patients (20%) presented VTE after the appearance of wAIHA, at a mean age of 52.5years. All patients had pulmonary embolus, associated with a deep venous thrombosis in 4 cases. At the time of VTE 7/8 patients had frank hemolysis (median hemoglobin level: 7g/dL) and 6/8 were outpatients with a low Padua VTE risk score. The frequency of usual VTE risk factor was similar in cases and controls. By contrast, lowest hemoglobin level was significantly lower in patients that experienced VTE (5.3 vs 7.2g/dL, p=0.016). During the first episode of wAIHA, patients with concurrent VTE had a more pronounced anemia (5.3 vs 7.4g/dL, p=0.026). At the time of VTE, anemia was more severe when no other precipitating factor was present (6 vs 8.9g.dL, p=0.04).
  
  
  CONCLUSIONS
  In our cohort, 20% of patients with wAIHA presented VTE. The vast majority of VTE occurred during severe hemolytic flares and were not attributable to usual VTE risk factors. VTE prophylaxis is advisable in any patient admitted for wAIHA, irrespective of Padua VTE risk score. Prophylaxis also seems reasonable for outpatients with marked hemolysis.
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France.
authors.forename: M
authors.initials: M
authors.lastname: Lecouffe-Desprets
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France. Electronic address: antoine.neel@univ-nantes.fr.
authors.forename: A
authors.initials: A
authors.lastname: Néel
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France.
authors.forename: J
authors.initials: J
authors.lastname: Graveleau
authors.affiliation: Pôle d'Information Médicale, Evaluation et Santé Publique (PIMESP), Hôpital Saint-Jacques, CHU de Nantes, 44093 Nantes, France.
authors.forename: C
authors.initials: C
authors.lastname: Leux
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France; Faculté de Médecine, Université de Nantes, 44035 Nantes, France.
authors.forename: F
authors.initials: F
authors.lastname: Perrin
authors.affiliation: Etablissement Francais du Sang Pays de Loire, 44011 Nantes, France.
authors.forename: B
authors.initials: B
authors.lastname: Visomblain
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France; Faculté de Médecine, Université de Nantes, 44035 Nantes, France.
authors.forename: M
authors.initials: M
authors.lastname: Artifoni
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France.
authors.forename: A
authors.initials: A
authors.lastname: Masseau
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France.
authors.forename: J
authors.initials: J
authors.lastname: Connault
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France; Faculté de Médecine, Université de Nantes, 44035 Nantes, France.
authors.forename: P
authors.initials: P
authors.lastname: Pottier
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France; Faculté de Médecine, Université de Nantes, 44035 Nantes, France.
authors.forename: C
authors.initials: C
authors.lastname: Agard
authors.affiliation: Service de Médecine Interne, Hôtel-Dieu, CHU de Nantes, 44093 Nantes, France; Faculté de Médecine, Université de Nantes, 44035 Nantes, France.
authors.forename: M
authors.initials: M
authors.lastname: Hamidou
mesh_terms: D000744:Anemia, Hemolytic, Autoimmune / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D016022:Case-Control Studies; D006801:Humans; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000209:etiology / Q000276:immunology*
keywords: Antiphospholipid antibodies; Auto-immune hemolytic anemia; Case–control study; Pulmonary embolism; Splenectomy; Venous thromboembolism