Hemoglobin Could be a Biomarker in COPD

An understanding of hemoglobin levels in patients with COPD could help guide disease management.

In patients with chronic obstructive pulmonary disease (COPD), anemia was associated with increased symptoms of the disease, leading investigators to suggest that hemoglobin could be a biomarker in COPD, according to a recent study published in ERJ Open Research.

Investigators conducted an analysis of hemoglobin from participants in the COPDGene study, an observational study to identify genetic factors associated with COPD, to examine symptoms, quality of life, functional performance, and acute exacerbations of COPD.

From 2,539 participants, investigators identified 366 (14%) as anemic, a condition where there is a decrease in red blood cells in the body. and 125 (5%) as polycythemic, a condition where there is an increase in red blood cells. A higher proportion of anemic patients were African Americans and other comorbidities.

Investigators found that compared with patients who had normal hemoglobin, those with anemia had increased symptoms, worse quality of life and increased morbidity but those with polycythemia did not. Anemia was associated with a 63% higher rate of severe exacerbations compared with normal hemoglobin.

Investigators found that there were no association between polycythemia and morbidity. Polycythemia tended toward higher rates of severe exacerbations but did not achieve statistical significance. Morbidity was increased at both extremes of the range of hemoglobin values for most outcomes. They point out, however, the prevalence of patients with polycythemia was low in this cohort, with estimates being in the 6% to 8% range.

The investigators suggest there may be an optimal range of hemoglobin for COPD patients.

This study confirms previous studies that found that high levels of hemoglobin were associated with longer survival in patients with COPD.

“We presented findings demonstrate in a large cohort of COPD participants that hemoglobin derangements are prevalent and are independently associated with varying degrees of increased morbidity across the spectrum of observed hemoglobin values. Examination of hemoglobin as a continuous variable suggests that values in both the anemia and polycythemia ranges are associated with increased morbidity, and that there may be an optimal range of hemoglobin values that is relevant for a COPD population,” investigators wrote.

This study, they say, offers support for further study of whether hemoglobin is a marker of disease severity and morbidity, according to HHS. In eight out of 10 cases, COPD is caused by exposure to cigarette smoke. In 2018, 16.4 million people, or 6.6% of adults, reported a diagnosis of any type of COPD (chronic bronchitis, emphysema, or COPD), according to the CDC.