Dysfunctional Breathing, in COPD: A Validation Study.

Area of Science:

• Respiratory Medicine
• Pulmonary Function Testing
• Diagnostic Accuracy

Background:

• The Nijmegen Questionnaire (NQ) is a widely used screening tool for dysfunctional breathing (DB).
• Previous validation of the NQ was limited to hyperventilation syndrome (HVS) and asthma populations.
• The NQ's utility in individuals with chronic obstructive pulmonary disease (COPD) remained unestablished.

Purpose of the Study:

• To evaluate the validity and reliability of the Nijmegen Questionnaire (NQ) in patients with stable COPD.
• To establish the NQ as a screening tool for dysfunctional breathing (DB) in the COPD population.

Main Methods:

• Principal component analysis was used to assess construct validity.
• Internal consistency reliability was determined using Cronbach's alpha.
• Convergent, divergent, and discriminant validity were examined in 84 stable COPD patients.

Main Results:

• A 16-item, three-factor solution explained 74.70% of the variability.
• High internal consistency (Cronbach's alpha = 0.94) was observed.
• The NQ score cutoff of '>23' detected DB with 95.92% sensitivity and 94.29% specificity.
• Significant correlations were found with BODE index (r=0.81), Borg scale (r=0.47), and CAT (r=0.49).

Conclusions:

• This study provides the first evidence of the NQ's validity and reliability for screening dysfunctional breathing in stable COPD patients.
• The NQ is a reliable and valid tool for identifying DB in individuals with COPD.
• The findings support the use of the NQ in clinical practice for COPD management.