Assessment of Oral Iron Absorption in Patients with Pulmonary Arterial Hypertension: A Clinical Study

Background: Iron deficiency (ID) is common in patients with pulmonary arterial hypertension (PAH). It is associated with worse clinical outcomes, including decreased exercise capacity and increased mortality. Previous studies have suggested that impaired gastrointestinal iron absorption may contribute to the high prevalence of ID in PAH patients.

Objective: The aim of this study was to determine in a standardized manner whether differences in oral iron absorption exist between PAH patients with and without ID and healthy controls.

Methods: This single-center prospective, cross-sectional cohort study involved 45 participants, divided into three groups: 15 PAH patients with ID in the past, 15 PAH patients without ID in the past and 15 healthy controls, who were age and sex matched to non-ID PAH patients. ID was defined by either recorded ID anemia in the past 3 years or clinical indication for i.v. iron supplementation. A standardized iron absorption test with 200 mg iron (II) glycine sulfate was performed by all participants after an overnight fast. Plasma iron levels and transferrin saturation (TSAT) were measured before oral iron intake and after 3 h and compared with the Mann-Whitney-U test.

Results: Patients with and without ID showed a similar increase of plasma iron and TSAT after 3 h. The increase in plasma iron and TSAT both patient groups was significantly lower (with ID: 95.5±70.6 µg/dl; 28.9±20.3%; without ID: 83.8±57.1 µg/dl; 26.7±16.1%) compared to healthy controls (151.9±62.4 µg/dl; 44.8±17.7%), p=0,004, [Fig. 1].

Conclusion: The standardized iron absorption test revealed a functioning but reduced iron uptake in PAH patients compared to controls. Thus, factors such as chronic inflammation may reduce the iron uptake in patients. Hence, this study supports the hypothesis of reduced iron absorption in PAH patients.

Fig. 1  Differences in iron absorption in PAH patients and healthy controls after 3 hours

Publication History

Article published online:
18 March 2025