Relationship Between Blood Eosinophils and Systemic Corticosteroid Therapy in COPD Exacerbation

PURPOSE: To assess the relationship between the duration of systemic corticosteroid therapy and blood eosinophil counts in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD). PATIENTS AND METHODS: This study included 292 patients with acute COPD exacerbations treated with daily intravenous injections of 40 mg/day methylprednisolone at the Department of Respiratory Medicine, Anhui No.2 Provincial People’s Hospital, Hefei, China. The study subjects were divided into two groups – (1) a low-dose group (n = 136) that included patients treated with methylprednisolone for less than or equal to 5 days and (2) a high-dose group (n = 156) that included patients treated with methylprednisolone for more than 5 days. The blood eosinophil counts were analyzed for both the patient groups, and an optimal cut-off value was calculated to distinguish between the two groups. The study endpoints were readmission or deaths within 30 days or 180 days and re-infections within 90 days after hospital discharge. RESULTS: The mean blood eosinophil counts in the low- and high-dose groups were 0.15 × 10(9)/L (0.11–0.23 × 10(9)/L) and 0.08 × 10(9)/L (0.04–0.12 × 10(9)/L), respectively (P < 0.01). Receiver operating characteristic (ROC) curve analysis showed that the cut-off value for the blood eosinophils to distinguish the two patient groups was 0.115 × 10(9)/L with a sensitivity and specificity of 72.8% and 72.4%, respectively. The number of readmissions between the two groups at 30 days and 180 days after hospital discharge did not show any significant differences (P = 0.292, P = 0.398). The follow-up data showed significantly higher rate of re-infections in the high-dose group (24/136) within 90 days after hospital discharge compared to the low-dose group (9/156) (P = 0.018). CONCLUSION: In patients with acute exacerbations of COPD, blood eosinophil counts of ≥0.115 × 10(9)/L were associated with effective response to corticosteroid therapy in ≤5 days.