Eosinophil levels, chronic bronchial infection linked to pneumonia risk in COPD

Reduced circulating eosinophils and chronic bronchial infection raise the risk for pneumonia in patients with COPD treated with inhaled corticosteroids, researchers reported in the American Journal of Respiratory and Critical Care Medicine.

Results from the post hoc long-term observational study of a historical cohort of 201 patients with moderate to severe COPD, as defined by Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommendations, showed that risk for pneumonia was about 63% higher in patients with chronic bronchial infection and about 97% higher in those with circulating blood eosinophil levels of less than 100 cells/µL. Additionally, the risk for pneumonia was nearly threefold higher among patients treated with inhaled corticosteroids who also had chronic bronchial infection and reduced circulating eosinophils.

The mean age of the patients was 70.3 years, 95% were men and the mean FEV₁ was 49%. Overall, 71.6% of patients were treated with inhaled corticosteroids, 57.2% had bronchiectasis and 20.9% had blood eosinophils counts less than 100 cells/µL. The researchers found pathogenic microorganisms in 42.3% of patients, of whom 22.4% met the definition of chronic bronchial infection. During the median follow-up of 84 months, 38.8% of patients had at least one episode of pneumonia.

“The results of this study suggest that the relationship between inhaled corticosteroid use and risk of pneumonia in COPD is modulated by the level of circulating eosinophil and presence of chronic bronchial infection. In patients with > 100 eosinophils/L, chronic bronchial infection increases this risk by itself. In those with < 100 eosinophils/L, the risk of pneumonia is increased independently of the presence of chronic bronchial infection, but it could be increased further by the use of inhaled corticosteroids,” the researchers wrote. “Collectively, these results support the need for careful monitoring of circulating eosinophils and sputum bacteriology in the clinical management of COPD patients, particularly in those considered for inhaled corticosteroid therapy.” – by Melissa Foster

Disclosures: The authors report no relevant financial disclosures.