Severity and phenotypes of dyspnea in asthma: impact of comorbidities

Dyspnea is a common but non-specific symptom of asthma, which in particular may be related to anxiety and hyperventilation syndrome, two frequent comorbidities of asthma.

We conducted a prospective multicentric cohort study in dyspneic asthmatic adults. Dyspnea was assessed using the Multidimensional Dyspnea Profile questionnaire. We described the sensory (QS) and affective (A2) domains of dyspnea and investigated the effect of poor asthma control, hyperventilation and anxiety on each dimension at baseline and after 6 months.

We included 142 patients (65% women, age:52 years). Dyspnea was severe and predominated on its sensory domain (median QS:27/50; A2:15/50). Uncontrolled asthma (ACQ?1.5), hyperventilation symptoms (Nijmegen?23) and anxiety (HAD-A?10) were present in 75%, 46% and 39% of cases, respectively. Uncontrolled asthma and hyperventilation symptoms were associated with higher QS and A2 scores: QS at 27(11) vs. 18(13) (p<0.001), A2 at 19(14) vs. 10(12) (p<0.001) in uncontrolled vs. controlled patients, and QS at 28(11) vs. 22(13) (p=0.001), A2 at 24(14) vs. 11(11) (p<0.001) in patients with vs. without hyperventilation symptoms. Anxiety was only associated with increased A2 (27(12) vs. 11(11), p<0.001). At 6 months, QS and A2 decreased of 7 and 3 points, respectively, in relation with changes in ACQ-6 and Nijmegen scores as well as the HAD-A score for A2.

In breathless asthmatics, dyspnea is severe and worsened but differentially modulated by uncontrolled asthma, hyperventilation symptoms and anxiety. A multidimensional phenotyping of dyspnea in asthmatics could be useful to understand its origins and personalize treatment.