Eosinophilic COPD Exacerbations Not Predictive of Moderate, Severe Relapses

In patients with chronic obstructive pulmonary disease (COPD), eosinophilic exacerbations, which are defined by known blood eosinophilic cutoff values, do not increase the risk for earlier recurrence of moderate and severe relapses, according to the results of an observational, prospective cohort clinical study. Results of the analysis were published in the journal ERJ Open Research.

Investigators in Budapest, Hungary, sought to explore the association between hospitalization with an eosinophilic acute exacerbation of COPD (AE-COPD) and future relapses. AE-COPD was defined as the acute worsening of respiratory symptoms in the prior 72 hours, including increased dyspnea, chest tightness, sputum production, and sputum purulence. All patients who were hospitalized with AE-COPD were divided into eosinophilic (≥2% of total leukocytes and/or ≥200 eosinophils∙µL^–1) and noneosinophilic subgroups, according to the results of complete blood counts on admission. The study participants were treated with a course of systemic corticosteroids.

A total of 152 patients were followed for 12 months (between February 15, 2017, and August 15, 2018) after hospital discharge or until experiencing their first moderate or severe COPD flare-up. In the current study, moderate exacerbations were defined as the need for outpatient treatment with systemic corticosteroids and/or antibiotics because of worsening COPD symptoms, whereas severe exacerbations required treatment in a hospital. Treatment failure was defined as readmission to a hospital with respiratory symptoms within 4 weeks following discharge after treatment of the index exacerbation.

Of the 152 study participants, 51 experienced an eosinophilic exacerbation as the index event and 101 experienced an initial noneosinophilic relapse. Individuals in the eosinophilic group exhibited less severe airflow limitation on admission, as demonstrated by higher forced expiratory volume in 1 second/forced vital capacity (FEV₁/FVC) values and lower C-reactive protein levels, compared with those who experienced noneosinophilic relapses. Additional features of the index event, including the use of antibiotic treatment, need for mechanical ventilation, length of hospital stay, and treatment failure, were similar between the 2 groups.

Results demonstrated that no significant difference was found in the time to the next moderate or severe exacerbation between the eosinophilic group (n=51; ≥2% of total leukocytes and/or ≥200 eosinophils∙µL^–1; median 21 weeks [range, 10-36 weeks]) and the noneosinophilic group (n=101; median 17 weeks [range, 9-36 weeks]; log-rank test: P =.63). Further, no link was shown when other cutoff values (≥3% of total leukocytes and/or ≥300 eosinophils∙µL^–1) were used for the eosinophilic phenotype.

In contrast, higher number of prior COPD exacerbations, lower FEV₁ at discharge, and higher number of pack-years were all associated with a shorter exacerbation-free time. Based on the results of a subgroup analysis of 73 patients, 48.1% of those with initial eosinophil exacerbations experienced noneosinophilic relapses on readmission.

The researchers concluded that the findings from the current study further elucidate the clinical interpretation of eosinophilic AE-COPD and can facilitate the development of targeted interventions that can be used to prevent recurrent exacerbations.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Csoma B, Bikov A, Tóth F, Losonczy G, Müller V, Lázár Z. Blood eosinophils on hospital admission for COPD exacerbation do not predict the recurrence of moderate and severe relapses. ERJ Open Res. Published online February 8, 2021. doi:10.1183/23120541.00543-2020