SESSION TITLE: COPD Poster Discussion
SESSION TYPE: Original Investigation Poster Discussion
PRESENTED ON: Sunday, October 25, 2015 at 01:30 PM - 03:00 PM
PURPOSE: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in United States (US) with an estimated prevalence of 12.7 million in US adults. The role of eosinophilic inflammation and steroid therapy is well accepted in asthma. Exhaled nitric oxide (FeNO) is a marker to determine eosinophilic airway inflammation. We sought to determine the exhaled nitric oxide levels in COPD subjects using population-based National Health and Nutrition Examination Survey data (NHANES).
METHODS: NHANES data was analyzed for the study period 2007 to 2010. Only spirometric studies that met or exceeded American Thoracic Society (ATS) criteria were included. COPD cases were identified by a post-bronchodilator FEV1/ FVC ratio < 0.70, confirming the presence of persistent airflow limitation. Cases without two mean reproducible FeNO, who ate Nitric Oxide (NO) rich foods, used inhaled steroids, or who reported respiratory illness were excluded from the study. Non-weighted samples were used for statistical analysis.
RESULTS: During the study period, 182 non-weighted COPD cases were identified, predominantly male (69.2%) and non-Hispanic Whites (72%). The mean age was 58.9 years (SD + 12.8 yrs.). FeNO was greater than 25 ppb in 19.2% of cases and 2.7% of cases were greater than 50 ppb. Cases with FeNO greater than 25 ppb were 35 years and older with mean age of 65.3 yrs (SD +10.9 yrs). Peripheral blood eosinophil counts were >/= 500 cells/ml in 14.7% of cases with FENO>25 ppb compared to 4.8% in cases with FeNO <25 (p-Value <0.05). However, no significant positive correlation existed between FeNO levels and blood eosinophilia (Pierson correlation p-value = 0.67)
CONCLUSIONS: In our analysis 19.2% of COPD cases have significant eosinophilic inflammation demonstrated by high levels of FeNO. Given the high prevalence of disease and beneficial role of steroids in eosinophil prominent COPD in decreasing exacerbations, measuring FeNO may determine the sub-set of COPD patients who may benefit from steroid or other immunotherapies. The use of peripheral eosinophilia in predicting airway eosinophilic inflammation in COPD was not substantiated by this study. In addition, our study is limited in that sputum eosinophilia was not measured.
CLINICAL IMPLICATIONS: COPD is a heterogeneous disorder where subjects with the same FEV1 may exhibit substantially different amounts of radiographic emphysema or vary in frequency of exacerbations. Precise characterization of COPD subtypes will be beneficial in developing targeted therapies.
DISCLOSURE: The following authors have nothing to disclose: Srinadh Annangi, Pradyumna Agasthi, Tirumala Rao Dammalapati, Avantika Chenna, Eric Flenaugh, Marilyn Foreman
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