GOLD stage 3 and 4 COPD patients who have high blood eosinophil counts have a higher risk of future hospitalisations due to pneumonia compared with individuals with the same degree of airflow limitation but lower eosinophil counts, according to research published in the European Respiratory Journal.
Researchers assessed 7,180 patients with COPD from the Copenhagen General Population Study, including 643 who had forced expiratory volume in 1 s (FEV1) <50% predicted between 2003 and 2011.
All primary discharge diagnoses of pneumonia during follow-up were recorded; of 6,537 patients with FEV1 ≥50% predicted, a total of 271 were hospitalised with pneumonia, and of 643 patients with FEV1 <50% predicted, 114 were hospitalised with pneumonia.
The data showed that among patients with COPD and FEV1 <50% predicted, the multivariable adjusted incidence rate ratio was 2.17 for pneumonia when comparing individuals with blood eosinophil counts of ⩾0.34×109 cells·L−1 versus <0.34×109 cells·L−1.
Risk of pneumonia did not differ by blood eosinophil count in individuals with COPD and FEV1 ⩾50% predicted.
The authors note that the high risk was driven by few individuals in the whole COPD cohort, and conclude that in individuals with COPD and FEV1 <50% predicted, blood eosinophil count ⩾0.34×109 cells·L−1 was associated with high risk of hospitalisation due to pneumonia.