Clinical Significance of Anemia and Serum Erythropoietin Level in Chronic Obstructive Pulmonary Disease

Background: Anemia is such a common and simple clinical finding that may underestimate its physiologic relevance in COPD.Objectives: To determine prevalence of anemia and measure serum erythropoietin in patients with COPD and to evaluate the effects of anemia on dyspnea, exercise tolerance, COPD severity, arterial blood gases and body mass index.Methods: This case-control observational study was conducted on 45 male stable COPD patients aged (54.3±5.4), in addition to 45 age matched (52.4±6.2), non smokers, health males. All participants were subjected to spirometry, measurement of serum iron and EPO, complete blood picture and arterial blood gases, and calculation of BODE index.Results: Anemia was prevalent among both COPD and controls (42.5% and 40%), all anemic controls had mild anemia while in COPD 1 of 4 anemic patients had moderate anemia. BODE index score was significantly higher in total COPD group compared to controls (4.15±2.70 vs. 1.37±0.49) and in anemic COPD compared to non-anemic COPD (6.21± 2.12 vs. 2.28±1.58). Among BODE index score FEV1% and 6MWD were significantly lower, while MMRC was signifi-cantly higher in total COPD group than controls and in anemic COPD than non-anemic COPD. Serum erythropoietin was non-significantly increased in total COPD patients than controls, while it was significantly increased in anemic COPD than non-anemic COPD (59.52±102.01 vs. 11.79±23.90). Serum iron was non-significantly decreased in COPD patients than controls, while it was significantly decreased in anemic COPD than non-anemic COOD. Hemoglobin was positively correlated with serum iron, FEV1%, PaO2 and 6MWD, while it was negatively correlated with serum erythropoietin, BODE index and MMRC among both total COPD group and anemic COPD subgroup. EPO was positively correlated with PaCO2, BODE index and MMRC while it was negatively correlated with serum iron, FEV1%, PaO2 and 6 MWD among both total COPD group and anemic COPD subgroup.Conclusion: Anemia seems to be common entity among both COPD patients and controls, it tends to be mild-moderate in COPD. In anemic COPD patients the expected hematological response was inconsistent as they had elevated serum erythropoietin, which indicate erythropoietin resistance. Anemia has negative impact on COPD patients, associated with reduced exercise capacity and increased dyspnea scale.