FeNO may predict treatment response in COPD exacerbations
MedWire News: Fractional exhaled nitric oxide (FeNO) levels may help predict treatment response in chronic obstructive pulmonary disease (COPD) patients who have been admitted to hospital for an exacerbation, say Hungarian researchers.
Measurement of FeNO is a non-invasive method of assessing levels of airway inflammation in patients with respiratory diseases, explain Balazs Antus (National Koranyi Institute for tuberculosis and Pulmonology, Budapest) and colleagues.
They add: “Most studies report elevated FeNO levels in patients with acute exacerbations of COPD. However, COPD is heterogeneous, and patient responsiveness to treatment with corticosteroids and bronchodilators is variable.”
To investigate the effectiveness of FeNO measurement for predicting response to treatment in COPD patients, the researchers studied 58 patients with the respiratory condition, aged an average of 61.8 years, who had been hospitalized for an exacerbation.
The patients’ lung function, and levels of FeNO and blood gases were measured at hospital admission and discharge.
The researchers found that the patients’ FeNO levels were significantly higher at hospital admission than at discharge, at a mean of 25.3 ppb versus 19.7 ppb, respectively, with no significant differences between men and women.
There was a significant positive correlation between FeNO levels at admission and post-treatment increases in FEV1 and percent of predicted FEV1, as well as between FeNO changes during treatment and post-treatment increases in these lung function parameters.
There was also a significant inverse correlation between FeNO levels at admission and length of hospital stay.
However, FeNO levels at admission and changes in FeNO levels during treatment did not correlate with increases in forced vital capacity, PaO2 (partial pressure of oxygen) or SaO2 (oxygen saturation) after treatment.
Receiver operating characteristic curve analysis revealed an optimum cut point of 26.8 ppb for FeNO as a predictor for a significant increase in post-treatment FEV1, with a sensitivity of 74% and a specificity of 75%.
Antus and team conclude in the journal Respirology: “The study demonstrated that FeNO levels at hospital admission correlated with improvements in FEV1 after treatment.”
They add: “FENO measurement appears to be a useful predictive tool for assessing the response to treatment in COPD patients with exacerbations.”
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By Mark Cowen