Unexplained iron deficiency in idiopathic and heritable pulmonary arterial hypertension

Thorax. 2011 Apr;66(4):326-32. doi: 10.1136/thx.2010.147272. Epub 2011 Feb 5.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anemia, Iron-Deficiency / blood
  • Anemia, Iron-Deficiency / etiology*
  • Epidemiologic Methods
  • Familial Primary Pulmonary Hypertension
  • Female
  • Ferritins / blood
  • Humans
  • Hypertension, Pulmonary / blood
  • Hypertension, Pulmonary / complications
  • Interleukin-6 / blood
  • Iron / blood
  • Male
  • Middle Aged
  • Postmenopause / blood
  • Premenopause / blood

Substances

  • Interleukin-6
  • Ferritins
  • Iron