Association of Asthma Education with Asthma Control Evaluated by Asthma Control Test, FEV1, and Fractional Exhaled Nitric Oxide

Background. Asthma education is an important adjunct for asthma control although the way asthma education affects asthma outcomes is poorly understood. The asthma control test (ACT), forced expiratory volume in 1 s (FEV1), and fractional exhaled nitric oxide (FeNO) have all been used as markers of asthma control. However, the use of FeNO as a surrogate marker remains controversial. Objectives. (i) To examine whether asthma education is associated with asthma control; (ii) to compare absolute levels and changes of ACT, FEV1, and FeNO over a year; and (iii) to evaluate whether FeNO can be used as an additional marker of asthma control. Methods. Fifty asthmatics with poor adherence (12 mild, 21 moderate, and 17 severe) received asthma education at study entry. Medications were unchanged for the first 3 months, and ACT, FEV1, and FeNO measurements were recorded at entry, 3, 6, and 12 months. Asthma control was assessed at each visit and patients were categorized as either "stable" or "unstable" asthmatics according to the global initiative for asthma (GINA) guidelines. Results. A significant decrease in FeNO and increase in ACT score were noted in the stable asthmatic group at 3 months (p < .001), and this persisted over 12 months. Significant correlations were seen between changes (Δ) in FeNO, ACT, and FEV1 over time. However, significant correlations between the absolute levels were not maintained over 12 months. A decrease of ≥18.6% in FeNO and a ≥3-point increase in ACT score (sensitivity: 80% and 73.3% and specificity: 83.3% and 87.5%, respectively) were associated with stable asthma control although the absolute levels were not. Conclusions. Asthma education may be useful to achieve stable control. In addition, changes rather than absolute levels of FeNO and ACT may be better markers of asthma control.