title: Unexplained iron deficiency in idiopathic and heritable pulmonary arterial hypertension.
abstract: BACKGROUND
  Anaemia is common in left heart failure and is associated with a poorer outcome. Many patients with pulmonary arterial hypertension (PAH) are anaemic or iron-deficient. This study was performed to investigate the prevalence of iron deficiency in PAH and to identify possible causes.
  
  
  METHODS
  All patients with idiopathic or heritable PAH diagnosed in 1995-2008 were identified. Controls were selected from patients with chronic thromboembolic pulmonary hypertension (CTEPH). Full blood counts were examined and any abnormality was investigated. Patients were excluded if they had a cause for iron deficiency. The prevalence study was based on 85 patients with idiopathic PAH and 120 with CTEPH. A separate group of 20 patients with idiopathic PAH and 24 with CTEPH with matching haemodynamics were prospectively investigated for serum factors affecting iron metabolism.
  
  
  RESULTS
  The prevalence study identified a point prevalence of unexplained iron deficiency of 50% in premenopausal women with idiopathic PAH compared with 8% in premenopausal women with CTEPH (p=0.002); 14% in postmenopausal women with idiopathic PAH compared with 6% in postmenopausal women with CTEPH (p=0.16); 28% in men with idiopathic PAH men compared with 2% in men with CTEPH (p=0.002); and 60% in patients with heritable PAH. The serum study showed that patients with idiopathic PAH had lower serum iron and transferrin saturations than those with CTEPH. Interleukin-6 levels correlated with iron levels (r=-0.6, p=0.006) and transferrin saturations (r=-0.68, p=0.001) in idiopathic PAH but not in CTEPH.
  
  
  CONCLUSIONS
  The prevalence of unexplained iron deficiency is significantly higher in idiopathic PAH than in CTEPH. This may be linked to interleukin-6.
authors.affiliation: Pulmonary Vascular Diseases Unit, Papworth Hospital NHS Trust, Papworth Everard, Cambridgeshire CB3 8RE, UK.
authors.forename: Elaine
authors.initials: E
authors.lastname: Soon
authors.forename: Carmen M
authors.initials: CM
authors.lastname: Treacy
authors.forename: Mark R
authors.initials: MR
authors.lastname: Toshner
authors.forename: Robert
authors.initials: R
authors.lastname: MacKenzie-Ross
authors.forename: Vijay
authors.initials: V
authors.lastname: Manglam
authors.forename: Mark
authors.initials: M
authors.lastname: Busbridge
authors.forename: Mark
authors.initials: M
authors.lastname: Sinclair-McGarvie
authors.forename: Jayantha
authors.initials: J
authors.lastname: Arnold
authors.forename: Karen K
authors.initials: KK
authors.lastname: Sheares
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Morrell
authors.forename: Joanna
authors.initials: J
authors.lastname: Pepke-Zaba
mesh_terms: D000328:Adult; D000368:Aged; D018798:Anemia, Iron-Deficiency / Q000097:blood / Q000209:etiology*; D004812:Epidemiologic Methods; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D005293:Ferritins / Q000097:blood; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood / Q000150:complications; D015850:Interleukin-6 / Q000097:blood; D007501:Iron / Q000097:blood; D008297:Male; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood; D017697:Premenopause / Q000097:blood
chemical_list: D015850:Interleukin-6; D005293:Ferritins; D007501:Iron