Anaemia affects nearly one in five patients hospitalized for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) and contributes to increased postdischarge mortality and readmission, a study has found. Its most common subtype is nutritional anaemia, followed by anaemia of chronic disease (ACD).
“Only nutritional anaemia was associated with an increased AECOPD readmission risk, whereas all subtypes were associated with higher postdischarge mortality,” the researchers said.
“Subtype-specific treatment with iron, vitamin B12, folic acid, or erythroid-stimulating agent (ESA) was associated with reduced postdischarge mortality risk, suggesting the benefit of targeted management,” they added.
Of the 32,152 COPD patients discharged from the hospital, 5,956 (18.5 percent) had anaemia, with nutritional anaemia being the predominant subtype (49.3 percent), followed by ACD (31.3 percent). [Am J Clin Nutr 2026;124:101402]
The presence of anaemia appeared to increase the risk of postdischarge mortality by 30 percent (adjusted hazard ratio [aHR], 1.30, 95 percent confidence interval [CI], 1.23‒1.37) and readmission risk by 8 percent (aHR, 1.08, 95 percent CI, 1.03‒1.14).
The highest postdischarge risk was seen among COPD patients with haematologic anaemia (aHR, 1.75, 95 percent CI, 1.54‒1.99), followed by those with nutritional anaemia (aHR, 1.29, 95 percent CI, 1.20‒1.39). Notably, only patients with nutritional anaemia were at greater risk of readmission (aHR, 1.18, 95 percent CI, 1.10‒1.25).
Targeted treatment
The effects of treatment varied by anaemia subtype. Iron, vitamin B12, and ESA all appeared effective at reducing postdischarge mortality among patients with nutritional anaemia. Folic acid and iron were beneficial for those with haematologic anaemia, while ESA and iron worked for those with ACD.
“In nutritional anaemia, iron therapy was associated with reduced postdischarge mortality, consistent with studies linking iron therapy to symptom improvement,” the researchers said. [ERJ Open Res 2021;7:00068; Am J Cardiovasc Dis 2022;12:38-41]
The high prevalence of iron deficiency in COPD is potentially cause by reduced intake, chronic inflammation, and comorbidities causing iron loss or malabsorption. [J Clin Med 2025;14:4154]
Increased oxidative stress, the main feature of COPD, contributes to disease progression, exacerbations, and comorbidities, which then leads to a higher risk of death. [Antioxidants (Basel) 2022;11:965; Int J Chron Obstruct Pulmon Dis 2025;20:2117-2130]
Apart from correcting anaemia, previous studies suggest that iron supplementation may improve redox balance in COPD patients with iron deficiency, which then helps alleviate oxidative stress. [Respir Investig 2022;60:510-521; Biomedicines 2021;9:1191]
“These findings suggest that targeted treatment may mitigate mortality risk in specific anaemia subtypes, although further research is needed,” the researchers said.
Study details
The current prospective observational cohort study involved patients with COPD aged ≥45 years hospitalized for severe exacerbations in a Belgian nationwide database. The research team used Cox regression models to explore association between anaemia or its subtypes and postdischarge mortality and AECOPD readmission, adjusted for potential confounders.
The association between anaemia treatment and mortality across anaemia subtypes was also examined using inverse probability of treatment weighting.
“Anaemia is a chronic condition frequently associated with COPD and has gained attention as a comorbidity in recent years,” the researchers said. [Lancet Respir Med 2023;11:1020-1034; Eur Respir Rev 2013;22:454-475]
Although anaemia has been associated with “increased exacerbation risk, mortality, and reduced quality of life in COPD … most studies have small sample sizes and do not fully account for comorbidities, for example, malignancy,” they added. [COPD 2016;13:100-109; Clin Respir J 2025;12:2546672]