Although hypoxia stimulation is believed to cause quantitative changes while inflammation causes qualitative changes, the effects of both on the hematopoietic system were balanced.11 In other words, in severe COPD, more severe inflammation leads to a clear EPO resistance or haematological malfunction.12 Its low prevalence may, at least in part, be attributed to the frequent need for LTOT in people with severe COPD. This evidence concerns the gene EPO and chronic obstructive pulmonary disease.