Prevalence of elevated FeNO, peripheral eosinophilia higher in patients with COPD, asthma

Patients with COPD and a history of asthma had a higher prevalence of elevated fractional exhaled nitric oxide levels compared with patients with COPD and no asthma history, according to new data published in Thorax.

“Our study supports clinically phenotyping COPD subjects with eosinophilic inflammation be independent of their asthma history and peripheral eosinophilia can be used as a surrogate marker in resource-limited settings,” Srinadh Annangi, MD, pulmonologist in the department of pulmonary critical care and sleep medicine at University of Kentucky College of Medicine, Lexington, and colleagues wrote.

Researchers analyzed data from the National Health and Nutrition Examination Survey from 2007 to 2010 on 3,110,617 patients (mean age, 59.3 years; 64.4% men) with COPD and a postbronchodilator FEV₁/FVC ratio less than 0.7. The researchers categorized patients with COPD into groups based on history of asthma (n = 2,655,739) or no history (n = 454,878).

In the cohort of patients with COPD, the overall prevalence of asthma history was 14.6%. The overall prevalence of peripheral eosinophilia was 36% (38.3% in patients with COPD and asthma; 35.6% in patients with COPD and no asthma history; P < .001).

The prevalence of FeNO 25 parts per billion was 14.3%; the prevalence was 28.7% in patients with COPD and a history of asthma and 13% in those with COPD without a history of asthma. Researchers observed significantly higher mean FeNO levels among patients with COPD and asthma history compared with those without asthma history (19.6 ppb vs. 15.8 ppb; P < .001).