Dysfunctional breathing in asthma is associated with poor asthma control after specialist management

Abstract

Background: Dysfunctional breathing (DB) is a respiratory disorder, in which the patient overbreathes or has an increased respiratory rate. DB may lead to an overestimation of the severity of asthma symptoms in asthma patients, and hence potentially to overtreatment. We wanted to investigate whether DB in subjects with asthma is associated with a poor treatment response after specialist management.

Methods: Subjects with asthma referred to a tertiary hospital clinic for evaluation were consecutively enrolled over one year and followed up 12 months later. Nitric oxide in exhaled breath (FeNO), the Nijmegen and ACQ questionnaire, and a bronchial challenge with mannitol were performed. Subjects with a Nijmegen score ≥23 was defined as having DB.

Results: A total of 94 asthma patients completed the follow-up and had data on the Nijmegen and ACQ questionnaire. A total of 127 subjects (24,41%) had DB at baseline. Asthmatic patients with DB had a significantly lower asthma control compared to asthmatics without DB (Mean(SD) ACQ: 2.29(1.19) vs 1.20(0.86), p< 0.01.)At follow-up, asthma patients with DB continued to have a higher ACQ (mean(SD)) compared to asthmatics without DB (1.56(0.96) vs 0.65(0.76), p<0.01.), despite no difference in level of AHR or airway inflammation. Furthermore, asthma patients with DB did not improve their ACQ score from baseline to follow-up, compared to asthmatics without DB (p=0.073 vs. p=0.000).

Conclusion: Among asthma patients newly referred for specialist management, DB is associated with a lack of improvement of symptom control after 12 months of treatment. Using only ACQ to monitor treatment in asthmatics with DB may increase the risk of overtreatment.