Combined assessment of childhood asthma control level using nitric oxide metabolites in exhaled breath condensate and lung function parameters

Abstract

Summary. The aim of this study was to estimate a prognostic value of nitric oxide metabolites (NOM) in exhaled breath condensate (EBC) as a marker of asthma control level. We examined 243 patients (of them, 162 males) aged 5 to 17 yrs with atopic asthma. Some of the patients were treated with corticosteroids (CS), others had not been never treated with CS (steroid-naive patients). Asthma control was assessed using the ACQ-5 questionnaire, the EBC NOM total concentration was measured with the Griess-Ilosvay's method modified by S.Soodaeva. In patients with good asthma control, EBC NOM concentration was 6.41 Ѓ} 2.33 μmol / L compared to 8.40 Ѓ} 2.59 μmol / L in patients with partial control and 8.47 Ѓ} 2.77 μmol / L in patients with poor control (р < 0.00001 for both). The EBC NOM concentration from the steroid-naive patients was significantly higher than that from the patients treated with CS. A correlation was found between ACQ-5 score and the total EBC NOM concentration in the whole cohort of patients (r = 0.30, p < 0.00001), in steroid-naive patients (r = 0.42, p < 0.00001), and in patients treated with CS (r = 0.43; p < 0.00001). Discriminant analysis was performed in patients with well controlled asthma and in a combined group of patients with partial and poor asthma control to estimate a prognostic value of EBC NOM and FEV1 as markers of asthma control level. The EBC NOM total concentration predicted asthma control in 63 % of the whole cohort, 75 % of the steroid-naive patients and in 70 % of the patients treated with CS. FEV1 predicted asthma control in 77.3 %, 75% and 74.75% of patients, respectively. Combination of EBC NOM total concentration and FEV1 predicted asthma control in 78.92 %, 79.44 % and 82.83 % of patients, respectively. Therefore, combination of EBC NOM total concentration and FEV1 is predictive for asthma control in 80 % of children with atopic asthma.