METHODS: We recruited 53 asthmatics consecutively referred for investigation to our Allergy Department. Age range was from 18-75 years, with asthma severity mild to moderate. Patients underwent history taking, physical examination, skin prick tests (SPTs), total IgE levels, CBC, FENO measurement, spirometry and bronchodilation test (BDT) with IB and salbutamol separately.
RESULTS: Forty-one patients showed a positive BDT: 11 to IB alone, 8 to salbutamol, 22 to both drugs. Forty-two patients were atopic (at least one positive SPT). In 5 patients FENO measurement was not successful due to poor compliance. FENO levels (ppb) were inversely correlated with the difference between FEV1 after IB and FEV1 after salbutamol (ΔFEV1postBDs): Pearson’s r = -0.413, p <0.005. After dichotomizing patients according to ΔFEV1postBDs, we found that the subgroup of patients (n=27) with a higher FEV1 after IB versus FEV1 after salbutamol showed lower FENO values with respect to the other subgroup (n=26): 32.6 ± 39.3 versus 50.7 ± 48 (Student t test: p < 0.05).
CONCLUSIONS: Our results suggest that in a population of asthmatics, mostly atopic, low FENO values are associated with a better response (higher FEV1 post BD) to ipratropium bromide versus salbutamol.