An observational investigation of dysfunctional breathing and breathing control therapy in a problem asthma clinic

Dysfunctional breathing (DB) is recognized as an associated problem in patients with asthma and may be identified by the Nijmegen questionnaire. We conducted an observational study to determine if breathing control therapy (BCT) improved Nijmegen scores or asthma-related quality of life in patients attending a problem asthma clinic.

Nijmegen and Mini Asthma Quality of Life (Mini-AQLQ) questionnaires were completed. Patients with a positive Nijmegen (> or = 23, DB) were referred for BCT and progressive exercise testing (PET) to seek confirmation of dysfunctional breathing. Follow-up questionnaire data were collected at 6 months.

A total of 102 patients were studied. The total mean Nijmegen score was 26.4 (range 1-61). Those with a score > or = 23 (DB group, n = 65, 64%) had significantly lower Mini-AQLQ (mean 2.83) than the non-DB group (n = 37, mean 4.12, 95% CI for difference 0.87, 1.87, p < 0.0001). There was a strong relationship between Nijmegen score and Mini-AQLQ (r = -0.63, p < 0.001) at baseline; 10 of 17 DB patients who completed PET showed inappropriate hyperventilation. Follow-up data, available for Nijmegen and Mini-AQLQ in 44 and 46 patients respectively, showed no significant change in either of these parameters.

The strong relationship between Mini-AQLQ and Nijmegen scores and poor relationship between Nijmegen scores and PET-identified inappropriate hyperventilation suggest that a positive Nijmegen score overestimates the presence of dysfunctional breathing in patients with moderate to severe asthma. We found no evidence that a moderate intensity breathing control intervention had any impact on Nijmegen scores or asthma-related quality of life in this patient group.