Anemia and inflammation in COPD

Background: Anemia in patients with COPD and its pathophysiology is an understudied issue. Methods: In a group of 101 COPD patients (FEV1 percentage of predicted, 37 +/- 2% [mean +/- SEM]; mean age, 61 +/- 1 years; 35% female gender), the prevalence of anemia and its relationship to body mass and weight loss, inflammatory parameters, and erythropoietin levels was determined. Data were compared to a control group (healthy persons with matched age) in order to identify potential factors that may influence the development of anemia in patients with COPD. Results: Anemia was diagnosed in 13 patients (hemoglobin levels < 13.5 mg/dL in male patients and < 12.0 mg/dL in female patients), which represents a prevalence of 13%. Anemic COPD patients showed elevated erythropoietin levels (41.8 +/- 25.4 U/L vs 16.3 +/- 2.9 U/L and an increased inflammatory response compared to nonanemic patients. A significant inverse correlation of hemoglobin vs erythropoietin (r = - 0.84, p < 0.01) was observed in anemic COPD patients, but not in the nommemic group. Conclusion: Anemic COPD patients show high erythropoietin levels, which may indicate presence of erythropoietin resistance. The latter may be mediated through inflammatory mechanisms, which is typical for anemia of chronic illness.