Characterization of airway inflammation in patients with asthma COPD overlap syndrome using FeNO levels

Abstract

Background: Asthma-COPD overlap syndrome (ACOS) is characterized by persistent airflow limitation with several features usually associated with asthma and with COPD. Airway inflammation is to be the provide mechanism of the asthma pathogenesis and is related to its symptoms. Purpose of the study: To characterize fractional exhaled nitric oxide (FeNO) levels that may be indicators of airway inflammation in patients with ACOS. Materials and Methods: The FeNO measurment was conducted on outpatient visit in 31 patients aged 40 years and older with moderate and severe COPD patients with the few features: no signs of acute exacerbation, post-bronchodilatator FEV 1 >12%, absolute eosinophil level greater 0.3x10E 9 /L. COPD severity was diagnosed according to the GOLD 2013 guidelines. Results of the study: The mean age of patients was 59.4±16.3. 19.4% of patients were females and 80.6 were males. All of the patient was previously diagnosed with bronchial astma, but for the moment of study the main diagnosis was COPD. Patients had a mean FEV1 54.2%±9.3% of predicted. The majority of patients had FeNO results greater than normal limits. Overall, percentages of patients with FeNO greater 25 ppb was 79%. Conclusions: The increased FeNO level could be one of the diagnostic keys of ACOS.