The increase of WBC was associated with the rapid decline of FEV1.[29] RDW indicates systemic hypoxic load, especially in pulmonary conditions.[30] Hypobaric hypoxia increased RDW.[31] However, RDW negatively correlated with FEV1.[32] Studies[33,34,35] have shown that RDW can reflect chronic inflammation in patients with COPD and pulmonary hypertension, and is positively correlated with C-reactive protein and nterleukin-6.The increase of WBC and RDW in PRISm may be the result of the dual effect of hypoxia and chronic inflammation. Here, CRP is linked to chronic obstructive pulmonary disease.