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 (FEV(1) 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 nonanemic 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.