What is the relationship between interstitial lung disease and iron deficiency anemia?

From the Guidelines

For patients with interstitial lung disease (ILD) and iron deficiency anemia, intravenous iron supplementation is recommended as the first-line treatment for anemia, given its superior efficacy and better tolerability compared to oral iron, as evidenced by a systematic review and meta-analysis of 5 randomized controlled trials 1. When managing ILD and iron deficiency anemia concurrently, it's crucial to address both conditions to improve patient outcomes.

• Treatment for ILD depends on the specific type, but it often includes corticosteroids, immunosuppressants, and antifibrotics.
• For iron deficiency anemia, intravenous iron formulations like iron sucrose or ferric carboxymaltose are preferred over oral supplements due to their higher efficacy in achieving a hemoglobin increase of 2.0 g/dL and lower treatment discontinuation rates, as shown in a study comparing IV and oral iron head-to-head 1. Key considerations in managing these conditions include:
• Regular monitoring of pulmonary function tests, complete blood counts, and iron studies to track disease progression and treatment response.
• Providing supplemental oxygen if oxygen saturation falls below 88% to mitigate hypoxemia's impact on anemia symptoms.
• Addressing chronic inflammation in ILD, which can contribute to anemia of chronic disease, and recognizing the cycle between hypoxemia from ILD and worsening anemia symptoms that requires simultaneous management of both conditions for optimal outcomes, as supported by the expert review on the management of iron deficiency anemia 1.

From the Research

Interstitial Lung Disease and Iron Deficiency Anemia

• Interstitial lung disease (ILD) is a group of pulmonary disorders characterized by inflammation and/or fibrosis of the lung parenchyma, which can lead to progressive dyspnea and respiratory failure 2.
• ILD can present with various symptoms, including dyspnea on exertion, cough, and respiratory distress, and can be associated with iron deficiency anemia in some cases 3.
• Idiopathic pulmonary hemosiderosis (IPH) is a rare disorder that can cause iron-deficiency anemia, hemoptysis, and alveolar infiltrates, and is a type of ILD 3.
• The diagnosis of ILD is typically made using a combination of clinical evaluation, imaging studies such as thoracic computed tomography, and physiologic assessment 2.
• Treatment of ILD depends on the underlying cause and severity of the disease, and may include antifibrotic therapy, immunomodulatory therapy, oxygen therapy, and lung transplantation 2, 4.

Nutrition and Interstitial Lung Disease

• Malnutrition is a common complication in patients with ILD, with a reported prevalence of 9-55% 5.
• Body mass index and fat-free mass have been shown to be important predictors of survival in patients with ILD 5.
• There is currently insufficient evidence to support the use of antioxidant or vitamin supplementation in patients with ILD, although registered dietitian nutritionists play an important role in the nutrition management of these patients 5.

Iron Deficiency Anemia and Interstitial Lung Disease

• Iron deficiency anemia can be a complication of ILD, particularly in cases of IPH 3.
• The diagnosis of IPH should be considered in children presenting with unexplained hypochromic, microcytic anemia and respiratory symptoms 3.
• Treatment of IPH typically involves corticosteroid therapy, which can lead to marked clinical improvement 3.