Burden of unexplained dyspnea: a single-center study

Unexplained dyspnea refers to unpleasant breathing sensations without any disorder being diagnosed. We aimed to study the burden of unexplained dyspnea, by assessing health-related quality of life (SF-36 questionnaire), characteristics of dyspnea (mMRC, multidimensional dyspnea profile (MDP) and Borg score at exercise), hyperventilation symptoms (Nijmegen questionnaire), anxiety and depression (HAD scale), exercise capacity (peak V̇O2) and ventilatory response to exercise. Of the 62 patients referred to our Dyspnea center, we included 29 patients with confirmed unexplained dyspnea after a complete systematic evaluation (a cause of dyspnea was found in 29 patients and 4 cases were excluded for missing values). They were aged 57 years [47;66], including 20 (69 %) women. All SF-36 scores were low: physical functioning 50 [33;75], limitation due to physical health 50 [0;63], limitation due to emotional problems 67 [0;100], fatigue 30 [15;43], emotional well-being 52 [44;66], social functioning 63 [38;75], bodily pain 45 [23;58], general health 50 [30;55]. Most patients (23 (79 %)) had activity-limiting dyspnea (mMRC≥2), 15 (55 %) had a low exercise capacity (peakV'O2<85 %) and 20 (74 %) had either exertional hyperventilation (threshold V̇E/V̇CO2>34) or low Vt expansion (peak Vt/FVC<40 %). Hyperventilation symptoms (Nijmegen>23) were present in 17 (59 %) patients, and associated with lower scores in some domains of the SF-36 questionnaire and higher HAD and MDP anxiety subscores. Our results suggest a heavy burden of unexplained dyspnea on physical and mental health. Expert centers may help in the diagnosis and thus enable earlier symptomatic management.