title: Risk of thromboembolism in patients with hereditary angioedema treated with plasma-derived C1-inhibitor.
abstract: BACKGROUND
  Plasma-derived C1-inhibitor (C1-INH) concentrates (pdC1-INH) have been used as safe and effective treatments for hereditary angioedema with C1-INH deficiency (C1-INH-HAE) for >30 years. Notwithstanding this, sporadic reports and a study into the high-dose therapy of neonates with C1-INH concentrate administered in an off-label indication raised concerns that this drug might increase the risk of thromboembolism.
  
  
  OBJECTIVE
  To investigate the incidence of thromboembolism and the background of the risk factors related to treatment with pdC1-INH.
  
  
  METHODS
  Our retrospective cohort study of 144 patients with C1-INH-HAE compared the incidence of thromboembolism and its risk factors in patients who received pdC1-INH with those who did not receive pdC1-INH as well as with those treated with danazol or with tranexamic acid.
  
  
  RESULTS
  During the observation period (29 years), 104 of the 144 subjects received pdC1-INH. The average dose per treatment was 573.59 IU. None of the patients used an indwelling central venous catheter. Multiple risk factors for thromboembolism were identified in 93 of the 104 patients treated with pdC1-INH. The incidence rate of thromboembolism was 0.0019/100 person-years in patients treated with pdC1-INH, whereas it was 0.0211/100 person-years in the not-treated group.
  
  
  CONCLUSIONS
  Our cohort study did not find any evidence for an increased risk of thromboembolism during treatment with pdC1-INH, despite the presence of multiple predisposing factors.
authors.affiliation: Hungarian Angioedema Center, 3rd Department of Internal Medicine, Semmelweis University, Budapest, Hungary.
authors.forename: Henriette
authors.initials: H
authors.lastname: Farkas
authors.forename: Kinga V
authors.initials: KV
authors.lastname: Kőhalmi
authors.forename: Nóra
authors.initials: N
authors.lastname: Veszeli
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Zotter
authors.forename: Katalin
authors.initials: K
authors.lastname: Várnai
authors.forename: Lilian
authors.initials: L
authors.lastname: Varga
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D054179:Angioedemas, Hereditary / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D050718:Complement C1 Inhibitor Protein / Q000008:administration & dosage / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012306:Risk; D013923:Thromboembolism / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D050718:Complement C1 Inhibitor Protein