Clinical, functional and molecular characteristics of anemia with comorbid chronic obstructive pulmonary disease

Abstract

The aim was to investigate an impact of different COPD phenotypes on clinical course of anemic syndrome. Methods. This was a single-center prospective observational cohort study. Patients with stable COPD and anemia were involved (n = 215). COPD was diagnosed according to GOLD criteria and anemia was diagnosed according to WHO criteria. The control group included 90 healthy subjects. COPD patients with anemia were stratified according to pathogenic variants of anemia and serum erythropoietin level. COPD symptoms, exacerbations, lung function, pulmonary hemodynamics, the type of airway inflammation, hematology parameters, serum erythropoietin, hepcidin 25, vitamin B12, folate, and iron homeostasis were assessed. Statistical analysis was performed using SPSS 24 software. The groups were compared using chi square test for nominal variables and Kruskal-Wallis test for continuous variables. Logistic regression was used to explore the relationships between variables. Results. Anemia was diagnosed in 63 (29.3%) of patients including common pathogenetic variants of anemia in 12 (19.0 %) of patients: iron deficiency 9 (14.3%) and vitamin B12 deficiency 3 (4.8%). This anemia variants were associated with shorter duration of respiratory symptoms and was not related to COPD phenotype. The clinical course of anemia was modified due to comorbid COPD in 51 (81.0%) of patients. Anemia with normal / high erythropoietin level was found in 31 (49.2%) of COPD patients and was hypochromic, microcytic and hyperregeneratory. Those patients had low serum levels of iron, vitamin B12, and folate, low total and latent iron-binding capacity of serum, and high levels of ferritin and hepcidine. This type of anemia was associated with frequent COPD exacerbations. Anemia with low erythropoietin level 20 (31.7%) was normochromic, normocytic, and normoregeneratory, with normal serum iron and ferritin levels, low iron-binding capacity of serum, and low hepcidine level. This type of anemia was associated with combined pulmonary fibrosis and emphysema and with pulmonary hypertension. Conclusion. Anemic syndrome in COPD patients is associated with COPD phenotype.