Eosinophilic phenotype was associated with better early clinical remission in elderly patients but not middle-aged patients with acute exacerbations of COPD.

Abstract

There is limited evidence of the relationship between peripheral blood eosinophils and clinical remission of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) at different ages, especially in elderly patients, which was the objective of the present study. This retrospective study stratified patients by age (elderly patients >65years old or middle-aged patients between 45 and 65years old) and analysed the relationship between blood eosinophils (≥2% or <2%) and AECOPD clinical remission at observing time points of 7, 14, 21 and 28days of hospitalisation. Student's t tests, Mann-Whitney U tests, Chi-squared or Fisher's exact tests were conditionally used to compare difference between groups. The unadjusted or adjusted Cox proportional hazards model was used to analyse the association between blood eosinophilic levels and cumulative clinical remission. Of 703 AECOPD cases analysed, 616 were elderly people (>65years), 312 of whom had eosinophilic exacerbations. There were statistically significant differences in leucocytes, eosinophils, neutrophils, lymphocytes, monocytes, high-sensitivity C-reactive protein levels (hs-CRP), and hospital costs between groups (P<.05, respectively). According to the chi-square analysis, eosinophilic exacerbation had a higher clinical remission rate at 7, 14 and 21days (all P<.05), but not 28days (P>.05). Among analysis through adjusted Cox proportional hazards model, eosinophilic exacerbation was significantly associated with a higher cumulative remission rate in elderly patients at 7, 14, 21days (all P<.05), but not 28days (P>.05). No significant association was observed in meddle-aged patients at any time points (all P>.05). Eosinophilic exacerbation was associated with better early clinical remission of AECOPD patients during hospitalisation. As stratified by ages, similar results were observed in elderly patients but not middle-aged patients. Blood eosinophils at different ages may be valuable in personalised management for AECOPD.