Dysfunctional breathing is common among asthma patients in a specialist setting, and results in a clinically significant underestimation of asthma control, which may potentially lead to overtreatment.

Background: The American Thoracic society (ATS) has suggested using fractional exhaled nitric oxide (FeNO) to monitor the level of eosinophilic (EOS) airway inflammation in asthma, but validation of the proposed cut-points is required in real-life populations. Objective: To validate FeNO cut-points suggested by ATS in relation to sputum EOS count in a real life population of asthma patients. Methods: All patients referred consecutively over a 12-months period for specialist assessment of asthma, were examined with FeNO and induced sputum, and reexamined 12 months later. The predicted values of a positive and a negative test (PPV and NPV) for a cut off 3% EOS in sputum were calculated. Change in FeNO was defined in accordance with ATS (> 20% or 10 ppb if FeNO was < 50 ppb). Results: 144 adult asthma patients were examined (59% female). Low FeNO (< 25 ppb) at baseline was found in 94 (65%), FeNO between 25 and 50 ppb in 34 (24%) subjects and high FeNO > 50 ppb in 16 (11%) subjects. The PPV for FeNO > 25 ppb and > 50 ppb to predict EOS 3% was 45% and 77%, NPV was 88% and 83%. The sensitivity decreased from 70% to 37% at the > 50 ppb cutoff. A significant reduction in FeNO was associated with a reduction in sputum EOS (p = 0.01). Conclusion: The findings support the validity of the FeNO cut-points suggested by ATS to monitor eosinophilic airway inflammation in asthma. However, in this real-life population, a large proportion of patients had intermediate FeNO values, which may limit the clinical usefulness of the ATS FeNO cut-points.

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Background and objectivePatients with severe asthma remain highly symptomatic despite high dose anti-inflammatory treatment. Level of asthma control is often assessed in the clinical setting with the asthma control questionnaire (ACQ). Separate components of the ACQ focus on different aspects of control. A high score on the third question (Q3) demonstrates activity limitations and may be caused by factors other than asthma such as physical deconditioning, concomitant cardiac disease and dysfunctional breathing patterns, leading to a overestimation of the severity of asthma. This could potentially lead to overtreatment. The aim of this study was to determine whether patients with severe asthma had a continuously high ACQ score, predominated by the third question despite treatment.MethodsIn a group of severe asthma patients, referred to the Royal Brompton hospital in London, UK, an evaluation of ACQ as monitoring tool was performed from May to July 2015, at an index clinic (v3) and two previous attendances (v1–2). The patients suffered from severe asthma (step 4 or 5 BTS/SIGN guideline treatment) and change in ACQ score over time (total and Q3) was compared with other measures of asthma severity such as medication burden and lung function.ResultsForty three patients (n = 27 females, 61.4%) of mean (SD) age: 56 (11) years were included. The total ACQ score (median (range)) at index was 2.67 (0.17–5.50), the ACQ score on Q3 was 3.00 (0.00–6.00) and mean (SD) FEV1 percent of predicted was 61.9 (±23.78). The total ACQ score was lower at index visit than the first visit (-0.17 (-1.83–1.50; p = 0.041). A change in ACQ score in Q5 was found (p = 0.019), whereas Q3 was unchanged. A change in FEV1 percent predicted was -0.62 (±12.11). A correlation between FEV1 percent predicted and both total ACQ score (p < 0.01) and Q3 ACQ score (p < 0.01) was found. There was no correlation between the changes in these three parameters.ConclusionIn patients with severe asthma there is a significant improvement in total ACQ score over three visits, but no improvement in exercise induced symptoms (Q3). This can be correlated with the fact that Q3 can reflect other symptoms than asthma.

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