Fraction of exhaled nitric oxide measurements in the diagnoses of asthma in elderly patients

OBJECTIVE: To assess the value of fraction of exhaled nitric oxide (FeNO) measurements in the diagnosis of asthma in elderly patients. METHODS: The clinical symptoms of 202 elderly patients were assessed with the asthma module of the International Study of Asthma and Allergies in Childhood test, which had been modified for the elderly patients, and the diagnostic routine for chronic obstructive pulmonary disease (COPD), which was based on the Global initiative for chronic Obstructive Lung Disease criteria. Of the 202 patients assessed, 43 were subjected to pulmonary function evaluations (spirometry) and FeNO measurements. RESULTS: Of the 202 elderly patients, 34 had asthma (23 definite and eleven probable), 20 met COPD criteria, 13 presented with an overlap of asthma and COPD, and 135 did not fit the criteria for obstructive pulmonary disease. Among the 43 elderly patients who were subjected to FeNO measurements, ten showed altered results (23.2%) and 33 had normal results (76.7%). The average value of FeNO in patients with definite and probable asthma undergoing this procedure was 29.2 parts per billion whereas that in nonasthmatic patients was 17.5 parts per billion (P=0.0002). CONCLUSION: We show a clear relationship between FeNO levels and asthma symptoms and previous asthma diagnoses in elderly patients.