EPO and chronic obstructive pulmonary disease: Contrary to our results, many researchers reported the higher-than-normal level of EPO in COPD patients and also explained their result with respect to hypoxia caused by chronic airway obstruction along with anemia of chronic disease31–33 In this regard, Sharma et al. conducted a study in 2015 on 200 COPD patients and reported a significant rise in EPO level with increasing the severity of the disease34.