Fractional Exhaled Nitric Oxide Has a Good Correlation with Asthma Control and Lung Function in Latino Children with Asthma

Abstract

Background. Although the measurement of fractional exhaled nitric oxide (FE_NO) has been recommended for observational studies and clinical trials of asthma, FE_NO has not been examined in studies of childhood asthma in Latin America, Objective. To examine the relationship between FE_NO and indicators of disease control or severity [asthma control test/childhood asthma control test (ACT/C-ACT), lung function, and exercise challenge test (ECT)] in Mexican children with persistent asthma, Methods. Children (6–18 years of age) with persistent asthma were consecutively recruited in a tertiary asthma clinic and divided into two groups, e.g. FE_NO < 20 parts per billion (ppb) and ≥20 ppb.Adequate FE_NO measurements were obtained in 134 (83.2%) of 161 eligible children, Results. Children with FE_NO<20 ppb had significantly higher scores on the ACT/C-ACT than those with FE_NO ≥ 20 ppb (median [interquartile range] :23 [20.8–25] vs. 21 [18–24], p = .002, respectively). Compared to children with FE_NO ≥20 ppb, those with FE_NO <20 ppb had a higher baseline predicted forced expiratory volume (FEV₁₎ [94% (92.5%–99.4%) vs. 83% (81%–89.9%), p = .001] and a lower probability of having a positive ECT (42.7% vs. 71.2%, p = .001). In addition, FE_NO was significantly inversely correlated with the participants’ ACT/C-ACT score and predicted FEV₁, and directly correlated with positive ECT, Conclusion. Among Mexican children with persistent asthma, low levels of FE_NO ( <20 ppb) are associated with better asthma control, and higher lung function.

• adolescents
• asthma
• asthma control test
• correlation
• fraction of exhaled nitric oxide
• Latin America
• school children