Exhaled Nitric Oxide as a Biomarker in different COPD phenotypes

Background: There are some evidence concerning Fractional exhaled Nitric Oxide (FeNO) in relation to COPD that highlights the potential role of FeNO as biomarker in monitoring the stability of COPD. It is known that patients with frequent exacerbations (FE) phenotype have more rapid decline of lung function, worse quality of life and higher mortality rates compared to patients with infrequent exacerbations (IFE). Given the importance of these events, it is important to identify patients at risk for exacerbations. Objective: To investigate if there is a difference in FeNO values between COPD patients stratified into FE and IFE phenotype. Methods: A total of 39 patients with COPD were divided into two groups, patients with FE and IFE. Both groups were subjected to FeNO measurement, pulmonary function tests and routine blood test. Results: FE group consisted of 21 patients, 85.7% male with mean age 66.52 (51±83) years. 33.3% were current smokers (CS) and mean pack-years (P-Y) was 42.14 (12±100). In IFE group were 18 patients, 72.2% male, mean age 67.67 (53±88) years. 27.8% were CS and mean P- Y was 27.44 (11±46). There was no significant difference in FeNO values between FE and IFE group (U=129.5, p