Assessment of cough in asthma patients attending clinic using the cough questionnaire for asthma (CQA).

BACKGROUND

Cough is a common and troublesome symptom in asthma that can persist despite treatment, but there is no tool to specifically assess cough in asthma patients. We developed the Cough Questionnaire for Asthma (CQA) to evaluate cough severity and its impact in asthma patients.

METHODS

We developed an 8-item questionnaire to assess cough severity and its impact, which was later refined to a 6-item version (CQA6). The questionnaire was validated in 289 asthma patients attending a hospital asthma clinic. Internal consistency was assessed using Cronbach's alpha. Concurrent validity was evaluated through correlations with the 6-item Asthma Control Questionnaire (ACQ6), the Cough Hypersensitivity Questionnaire (CHQ), and both patient and physician cough severity ratings (in a 5-point Liker scale). Repeatability was assessed using intraclass correlation coefficient (ICC) and Bland-Altman analysis of responses obtained 3-6 months later.

RESULTS

CQA6 demonstrated excellent internal consistency (Cronbach's alpha =0.898) and strong correlations with patient-rated cough control (r=0.769), physician-rated cough control (r=0.692), and ACQ6 scores (r=0.672). CQA6 showed moderate correlation with CHQ scores (r=0.574). In longitudinal assessment, changes in CQA6 scores correlated strongly with changes in patient-assessed cough control (r=0.608) and ACQ6 (r=0.647). The ICC for CQA6 was 0.800 in stable patients, demonstrating good repeatability.

CONCLUSIONS

CQA6 is a reliable and valid tool for assessing cough severity and its impact in asthma patients. It will help in the evaluation of cough as an important contributory symptom for asthma management.